Colostrum harvesting

Colostrum harvesting

colostrum harvesting
Newborn baby being fed colostrum by syringe

Colostrum harvesting is collecting colostrum from the breast. Colostrum is the first secretion from the mammary glands, rich in antibodies. It is a sticky liquid from the nipples which is made before the milk has ‘come in’ (before breast milk is produced). It is produced from around the 20th week in pregnancy, up until the first few days after the baby has been born.

Colostrum is easily digested and is packed with proteins, vitamins, minerals and salt which helps prevent dehydration and help boost the baby’s immune system. Colostrum helps the passing of meconium (the baby’s first bowel movement) which also assists in preventing jaundice.

Antenatal colostrum harvesting is when the mother collects or expresses the colostrum from the breast during pregnancy before the baby is born and freezes for use after birth.

The frozen colostrum is taken to hospital and stored until it is required, where it can be defrosted and fed to the baby.



The link between diabetes and colostrum harvesting

Many babies born to diabetic mothers can have low blood sugar levels after birth putting them at risk of neonatal hypoglycaemia and jaundice.

neonatal jaundice
Newborn baby receiving light therapy due to neonatal jaundice

Neonatal hypoglyceamia (low blood sugar levels) is the biggest post birth complication we see in our support group, even when the mother’s blood sugar levels have been well controlled.

To raise blood sugar levels the baby needs to feed as much as possible.  Even though many mothers manage to successfully breast feed, some babies still require further top up feeds and some have difficulties feeding and therefore require bottle or cup feeds.  In more concerning situations, babies born to gestational diabetes mothers may need an NG tube or a glucose/dextrose infusion.

The best thing to raise blood sugar levels in the baby is colostrum.  If you choose not to breastfeed or cannot for any reason, formula can be used to raise blood sugar levels instead.


Increased risk of neonatal hypoglycaemia

Gestational diabetes hypoglycaemia in the newbornBabies born to diabetic mothers have very likely been subject to high blood glucose levels whilst growing in the uterus at some point.  In response to processing these high blood glucose levels from the mother during the pregnancy, the baby overproduces their own insulin to compensate.

Once born, the baby may still overproduce insulin amounts in their body, struggling to regulate insulin production and causing low blood glucose levels.

The baby may struggle to raise their blood sugar levels without additional help and so this is where additional colostrum top up feeds can really help.


Things that can be done to help control babies born to diabetic mothers blood glucose levels after birth

  1. It is really important to try to gain control and keep blood glucose levels stable throughout pregnancy, especially towards the end and during labour.  Avoiding any high readings becomes extremely important right at the end, so don’t be tempted to give in to temptations in those last few days, thinking “oh it won’t make much difference now I’m so close to the end!”. warning2Despite what you may be told, avoid energy drinks or high sugar foods which may be suggested such as flapjack during labour. Keeping your blood sugar levels stabilised gives the baby the best chance to normalise their own insulin production and blood glucose levels before they are born
  2. Harvesting colostrum so that you have some readily available should baby require top up feeds
  3. Have skin to skin and try to initiate a breast feed as soon as possible, ideally straight away
  4. Feed baby as regularly as possible, ideally every 3 hours.  If you have a sleepy baby then you may need to strip baby down, change their nappy etc. to help rouse them and encourage them to feed.  If you have any difficulties breast feeding then don’t be afraid to ask for help and support from the midwives and nurses.  Some hospitals have breast feeding consultants, support workers and specialist breastfeeding midwives.


Experienced breast feeding mothers benefit too

Many ladies who are experienced breast feeding mothers do not understand the need for expressing colostrum before birth. Firstly, each and every baby can be very different, along with different complications such as issues with latching and/or tongue tie, preventing them from breast feeding. GD babies can be very sleepy and may also struggle to latch, wake for feeds or feed effectively.  Some babies may feed well from the breast but still require additional feeds on top of regular breast feeds to keep blood sugar levels stable.


Colostrum v’s formula

Formula will raise blood sugar levels, however research suggests that breast feeding colostrum has a better effect on raising blood sugar levels than formula:

RESULTS: Infants who were breastfed in the delivery room had a significantly lower rate of borderline hypoglycaemia than those who were not breastfed in the early postpartum period (10% versus 28%; Fisher’s exact test., P = 0.05,). Likewise, infants breastfed in the delivery room had significantly higher mean blood glucose level compared to infants who were not breastfed in the delivery room (3.17 versus 2.86 mmol L(-1), P = 0.03). Additionally, breastfed infants had a significantly higher mean blood glucose level compared to those who were formula fed for their first feed (3.20 versus 2.68 mmol L(-1), P = 0.002).

CONCLUSIONS: Early breastfeeding may facilitate glycaemic stability in infants born to women with gestational diabetes.

Effects of early breastfeeding on neonatal glucose levels of term infants born to women with gestational diabetes

Can’t I just breast feed or express when baby is born?

Yes, of course you can breast feed when baby is born and we actively encourage this. However each baby is different, some babies may have difficulty feeding for many reasons and some may need additional top up feeds on top of breast feeding. Expressing can be difficult and having a supply harvested ready for use can be helpful and reassuring should your baby need it.


Colostrum feeding babyLactation aiding foods/drinks and sweet things to increase sugar amounts in colostrum are not necessary

Colostrum itself is extremely potent and sweet (we call it ‘liquid gold’). Your normal GD friendly diet is best and you don’t want to cause any unnecessary high blood sugar levels for yourself and your growing baby. Stay well hydrated by drinking plenty of fluids.

Please note that whilst lactation cookies, teas, oats, fenugreek etc. may be advocated to assist milk production, there is no evidence to support these things increasing colostrum production during pregnancy.

You will still have gestational diabetes at this time and so it is important to not risk eating or drinking things which could cause high blood sugar levels, in fact this could have detrimental effect on your baby’s blood sugar levels after birth and so should be avoided.


dateWhen to start colostrum harvesting

After 36 weeks is the usual time for mothers with gestational diabetes, based on induction or planned delivery of around 38 weeks+. But giving yourself 2 weeks before baby is due or planned is a good idea.  It is advisable to speak with your diabetic team regarding when would be the best time for yourself.

milk collection shells
milk collection shells from Medela

It is not advised to express in order to collect colostrum before this time as expressing may induce contractions early.

However, if you are leaking colostrum then do not waste it! All colostrum is full of goodness and so this can be sucked from the nipple with a sterile syringe and frozen. If you start to get strong Braxton Hicks or contractions then stop expressing. If you are leaking lots through the day, then you may want to purchase some milk collection shells so that every little drop of colostrum can be saved, rather than letting it soak into breast pads and be wasted.


Will my diabetic team or midwife discuss colostrum harvesting with me?

Some diabetic teams will advocate colostrum harvesting, giving out supplies or packs for colostrum harvesting, along with guidance and support on how to express. Other teams may look at you like you’ve grown another head when you mention it! Just like with everything else related to gestational diabetes, advice, support and information can vary dramatically from one hospital to another.

In a survey we ran in 2016, from 1,308 answers 77% (1,005 ladies) were not happy with the information and support giving around colostrum harvesting at their hospital.

If you wish to harvest colostrum ready for birth, then speak with your diabetes team and breast feeding specialists and if they are unaware, then explain the benefits and reasons why. As long as they have space in a freezer for your colostrum to be stored during your labour, then there should be no reason why you can’t harvest.

Some may suggest that they would prefer to use formula instead of colostrum if the baby requires top up feeds. This is your decision and if you wish to use colostrum instead, as long as it has been stored correctly, there is no reason for formula to be used instead.


syringes for colostrum harvestingHarvesting colostrum

Some Mums may find they leak colostrum, others will need to express to extract colostrum from the breast.

Please do not panic or worry that you are not leaking colostrum or do not notice any difference in your breasts. This does not mean you will not be able to harvest colostrum.


Equipment needed

Sterile syringes should be used to collect the colostrum and is what is recommended for use in the UK.

1ml sterile syringes are best for collecting colostrum which can be bought in pharmacies or online.  We find 1ml the best as each syringe can be defrosted and used without any wastage.

Capped syringes (syringes with caps or lids) are not necessary but may be preferred to eliminate contamination risks. However these can be hard to get hold of and quite expensive.


Ask for some syringes

In the first instance ask your diabetic team or midwife if you could have some syringes. Sterile syringes without caps will serve the same purpose as long as the filled syringe is placed inside the wrapper or a clean plastic bag (like a sandwich/freezer bag) and chilled or frozen straight away. Or you could ask your hospital for some syringe caps.

Your diabetic team/midwife may be able to supply syringes for free so it is worth asking! Some teams even offer colostrum harvesting packs such as these

Colostrum harvesting pack
ask your diabetic team if they provide colostrum harvesting packs or syringes for free

Purchasing syringes

Sterifeed colostrum collector syringesIf your hospital cannot provide you with syringes for colostrum harvesting and you need to purchase some syringes, then these Sterifeed colostrum collector syringes which are individually packed and sterile, are suitable for use in most hospitals

(please check with your hospital as we’ve had one mother in our support group be told that they had to use a specific syringe).


How to harvest colostrum – antenatal expressing of colostrum

Step 1. Always wash your hands before you start expressing.wash hands

Expressing after a shower or bath can be extremely beneficial to colostrum harvesting. Some ladies also find a warm compress such as a hot flannel or holding a hot water bottle to the breasts aids colostrum harvesting.

Make sure you have your colostrum harvesting equipment ready to hand such as your sterile syringes, sterile spoon or pot.

Step 2.  Sit in a comfortable position. You need time, space and to be able to relax. Some mothers find it helps to sit in the baby’s nursery or to look at scan pictures of their baby.

Step 3. Gently massage your breast, massaging from the back of your breast towards the nipple. Use kneading, circular and stroking movements to massage. You should be gentle when massaging, you can use one or both hands and it should not cause any discomfort. Some mothers find it works well to massage whilst in the shower or bath.

c hold on breastStep 4. Find the correct place to press using your thumb and index finger.

This is usually a few centimetres back from the base of the nipple, or move up slightly until you find where the breast feels firmer and a change in the texture of the breast tissue is felt.

Cup the breast using the ‘C shape’ position with the thumb and finger.

Step 5. Using the pads of your fingers rather than the fingertips, press back into the breast, squeezing gently for a few seconds and then releasing.

colostrum harvesting motionYour fingers should not touch the nipple, they should work on the outside of the areola but should not tug, squeeze, pinch or drag your nipple.

Squeeze and release, squeeze and release. Continue to repeat this motion to mimic the action of a baby sucking.

(This picture shows beads of colostrum forming on the nipple, but it may take many, many attempts before any colostrum is seen – do not let this put you off! This is completely normal)

colostrum harvesting beads of colostrumStep 6. If any beads of colostrum form they can be collected in 3 different ways depending on how much colostrum is produced.

colostrum harvesting collecting in a syringe6a) Beads of colostrum on the nipple: The easiest way to collect colostrum which is forming beads on the nipple is to suck it directly from the nipple into a sterile syringe. This can be fairly tricky and you may need a little help in sucking up the colostrum.

  • Have a sterile syringe ready to use. DO NOT pull the plunger out. To use the syringe it must have the plunger pushed fully into the syringe.
  • Place the tip of the syringe over the bead of colostrum and with your other hand, gently pull up the plunger slightly (but only enough to suck up the bead of colostrum).collecting colostrum into a syringe
  • If the colostrum is pulled too far down the syringe, flick the syringe to remove any air bubbles and very gently push up the plunger. This will push the colostrum back nearer the top BUT do this carefully! Many ladies have done this, pressed too hard and lost all the colostrum out the end of the syringe.
  • Continue expressing and keep adding to the syringe each time a bead forms.

colostrum harvesting continue adding to the syringe

6b) Slightly more flow can be expressed onto a sterile spoon

  • colostrum harvesting onto a spoonIf you are getting more flow than just beads forming, you may want to try expressing directly onto a sterile spoon which involves catching the droplets with the spoon.
  • Once you have some on the spoon, you can then use your syringe to suck up the colostrum.
  • Use the same technique mentioned above to suck up the colostrum and move the colostrum up the syringe to the top.

6c) Heavier flow can be expressed into a sterile pot

  • colostrum harvesting into sterile containerIf you’re lucky enough to get larger volumes of colostrum then you may find it easier to express straight into a sterile container. This involves holding your breast over the container and allowing the colostrum to flow or drop into it.
  • Once you have finished expressing, the colostrum can then be sucked straight into a sterile syringe.

Step 7. After expressing in this position for a while, move your hand around to hold the breast in the ‘C position’ from another angle and repeat the squeeze and release motions again.

colostrum harvesting beads of colostrumStep 8. Repeat the whole process on the other breast.

Step 9. When you have finished expressing, replace the syringes into their wrappers or place a cap on them.

colostrum harvesting label Step 10. Label your syringes with your name, hospital number and most importantly the date.

Many ladies have forgotten to do this in the past which has resulted in wasted colostrum.

You can continue adding to the same syringe for 5 days (as long as it is kept refrigerated) but the date you first expressed is the date that should be written on the syringe.

colostrum harvesting boxStep 11. Refrigerate or freeze your colostrum. Use a tupperware box or a suitable freezer bag to store your colostrum.

Don’t let your hard work and efforts go to waste! Make sure your colostrum is stored correctly until you need it.

For further details on storing colostrum, please read below.



*Please note: The mother in the video above is expressing breast milk and so please do not expect this amount of milk to flow. Colostrum can be very thick and sticky and may form in very small droplets, rather than ‘squirting’ out when expressing. This is completely normal! We recommend collecting colostrum in small syringes (1-2ml) so that small top up feeds can be defrosted as and when needed to avoid any wastage of defrosted colostrum

Further guidance on hand expressing


Hand expressing is advised for antenatal colostrum harvesting. Hand expressing is when you use your hand to massage and squeeze the breast to extract colostrum as the guide above explains.

Further guidance on hand expressing can be found through the many links below.

Please remember, you will not be expressing milk as breast milk will not ‘come in’ until after baby is born. Also don’t expect great amounts of colostrum unless you’re really lucky! You may only manage a bead or two, but don’t give in…the more you express, the more you collect!.. Every drop of liquid gold counts!

Colostrum will not ‘run out’ or be used up by the time your baby is born, you will continue to produce colostrum until your milk comes in, so please do not worry that your supply will disappear by expressing.

Here is a video to demonstrate how to hand express, but please note that the recommendations around freezing are different in the UK. Sterile syringes are the preferred way to store harvested colostrum – this can easily be given straight into the baby’s mouth when required.  These should then be clearly marked with your name and date

Here is another video showing expressing, this shows a lady actually expressing from the breast, but please bear in mind that colostrum is much thicker and stickier than breast milk and so it doesn’t tend to flow from the breast like this and another video here from UNICEF.

Can I use a breast pump?

If you are getting a heavier flow of colostrum then breast pumps can cause a lot of wastage as colostrum is so sticky and can get stuck in the breast pump tubes.

If you are really struggling to get any droplets to form then you may find using a breast pump is enough to encourage your colostrum to bead or form droplets. For myself personally, I could only harvest colostrum by using an electric breast pump. It was just enough to get beads of colostrum to form for me to suck up.

Breast pumps should be used with caution antenatally due to the expression being stronger than with hand expressing. If you decide to use a breast pump then use it sensibly and stop expressing if you notice and tightenings or contractions.

colostrum storingStoring colostrum

You should only store colostrum in a sterilised container, ideally a sterile syringe.  Ensure the syringes you use are sterile before using. Cold water sterilisation is the best method for non-sterile syringes.

Label every syringe with your name and the date it was collected, hospital stickers from your handheld notes are great for this if you have spares!


How long to store colostrum for

frozen colostrum

  • in the fridge for up to five days at 4ºc or lower (store in the main part of the fridge, not the door). You can add to the same syringe for a couple of days before freezing but you should date it as the first date collected
  • for two weeks in the ice or freezer compartment of a fridge
  • for up to six months in a freezer


Colours and consistency of colostrum

colours of colostrum
this colostrum is from the same mother, notice the difference in colour

Colostrum can vary dramatically in colour, from dark orange/brown, yellow/cream to pale/clear.

Please do not panic if yours does not look the same colour as that the examples shown here, or if yours changes colour and consistency over a few expressing sessions, this is normal.

Consistency can be very thick and sticky, or more watery and thinner.

All colostrum is packed with the goodness your baby needs, so please do not worry.  If you express and get pink colostrum then this may mean that some blood may be present.  Small amounts of blood are not harmful to the baby and so it should not be discarded. If you have any concerns then please speak to a medical professional.

colostrum syringe






Frequency of colostrum harvesting and amount required

Collect as much as you would like and are able to.  Bear in mind that a newborn baby’s tummy is the size of cherry on Day 1, the size of a walnut by Day 3 and the size of an apricot by 1 Week.  You don’t need huge amounts, but any harvested colostrum will not go to waste.

Some mothers have used expressed colostrum when returning home from hospital and some even use it for the first stages of weaning at 6 months or for teething lollies! Colostrum has many uses including using it to ease sore nipples from feeding or in skin or eye infections of baby. It really is liquid gold!

You can express as often as you feel comfortable to do so.  Most mothers prefer to express daily after a warm shower or bath.


ARGH…I’ve been trying for ages and I’m not getting any colostrum!

colostrum harvesting struggle
Its common for it to take days or longer to collect this amount, do not panic. This is actually a very good amount!

Don’t panic.  It is not easy expressing and harvesting colostrum and many (in fact the majority) really struggle to do it.

It may take many days of trying and a lot of frustration before you even see a bead of colostrum!

If you’re happy to continue then keep trying everyday.  If it’s stressing and upsetting you then stop putting pressure on yourself.  Only you can choose if you wish continue or not.  It is is not necessary to harvest colostrum and so please do not feel that you HAVE to do this.

Many ladies that have tried expressing colostrum have found that they have had better breast feeding experiences compared to previous births where they’ve struggled to breast feed.  This is obviously not a given, but even if you struggle to actually collect colostrum, know that the process is helping prepare your body for feeding your baby.  If you collect some colostrum then it’s a bonus!


Not being able to harvest colostrum has NO indication of lack of milk production or how well breast feeding will go

The amount of colostrum harvested, or lack of, prior to birth does not mean that you will not be able to breast feed or express once your baby has been born. I repeat, it has no impact or indication of lack of milk production. Please do not feel that if you can’t express colostrum that you will not be able to breast feed or produce milk.


  1. Try expressing after a warm bath or shower
  2. breast warming pads for colostrum harvesting
    breast warming pads

    Hold warm flannels or even a hot water bottle on your breasts before expressing to increase circulation. You can also purchase breast warming pads which may be helpful

  3. RELAX, Relax, relax – stressing will not help, if you can do it great, if you can’t it is not the end of world and it has no relation as to whether you will be able to breast feed or not OR how much milk you will have
  4. Massage your breasts before expressing
  5. Don’t touch the nipple during expressing or try to express too close to the nipple – many ladies say that they have sore nipples following trying to express.  It shouldn’t hurt. Pulling fingers back to outside of areola then forwards really milks the ducts
  6. Drink plenty of fluids
  7. Looking at scan pictures, sitting in your nursery or baby’s room, rocking something like a toy like you would your baby, thinking of your baby and listening to a newborn baby cry have all been tips to help!
  8. Ask for help! Speak with midwives, your health visitor, local breast feeding peer supporters and lactation consultants in your area for tips and advice on expressing. There are lots of people out there who can help you, but you may have to go online and search for local specialists. Try The Breast feeding network or La Leche League


Is it safe to harvest colostrum when taking Metformin?

Yes – Metformin is often used in ladies who have PCOS.  PCOS causes insulin resistance and so many mother’s with GD may have PCOS.  Both PCOS and insulin resistance can be linked to low milk supply. For further information regarding metformin and PCOS please read more here


baby being fed colostrum by syringe

Helpful links:


Expressing your milk before your baby arrives: antenatal expression of colostrum

PDF Leaflet on antenatal expression of colostrum

How to guide: expressing breast milk by hand

The Importance of Colostrum

Expressing and storing breast milk

Diabetes and Breast Feeding, La Leche League GB

UNICEF The Baby Friendly Initiative – Diabetes

More links for colostrum harvesting can be found on our Pinterest account

Antenatal Expression of Colostrum



breast feeding colostrumResearch

Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomised controlled trial, Published: 03 June 2017

Infants of women with diabetes in pregnancy are at increased risk of hypoglycaemia, admission to a neonatal intensive care unit (NICU), and not being exclusively breastfed. Many clinicians encourage women with diabetes in pregnancy to express and store breastmilk in late pregnancy, yet no evidence exists for this practice. We aimed to determine the safety and efficacy of antenatal expressing in women with diabetes in pregnancy.


We did a multicentre, two-group, unblinded, randomised controlled trial in six hospitals in Victoria, Australia. We recruited women with pre-existing or gestational diabetes in a singleton pregnancy from 34 to 37 weeks’ gestation and randomly assigned them (1:1) to either expressing breastmilk twice per day from 36 weeks’ gestation (antenatal expressing) or standard care (usual midwifery and obstetric care, supplemented by support from a diabetes educator). Randomisation was done with a computerised random number generator in blocks of size two and four, and was stratified by site, parity, and diabetes type. Investigators were masked to block size but masking of caregivers was not possible. The primary outcome was the proportion of infants admitted to the NICU. We did the analyses by intention to treat; the data were obtained and analysed masked to group allocation. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12611000217909.


Between June 6, 2011, and Oct 29, 2015, we recruited and randomly assigned 635 women: 319 to antenatal expressing and 316 to standard care. Three were not included in the primary analysis (one withdrawal from the standard care group, and one post-randomisation exclusion and one withdrawal from the antenatal expressing group). The proportion of infants admitted to the NICU did not differ between groups (46 [15%] of 317 assigned to antenatal expressing vs 44 [14%] of 315 assigned to standard care; adjusted relative risk 1·06, 95% CI 0·66 to 1·46). In the antenatal expressing group, the most common serious adverse event for infants was admission to the NICU for respiratory support (for three [<1%] of 317. In the standard care group, the most common serious adverse event for infants was moderate to severe encephalopathy with or without seizures (for three [<1%] of 315).


There is no harm in advising women with diabetes in pregnancy at low risk of complications to express breastmilk from 36 weeks’ gestation.


Australian National Health and Medical Research Council

Prof Della A Forster, PhD'Lisa H Amir, PhD

Importance of early first feed for babies of diabetic mums

It has been recognised that babies of diabetic mothers are at greater risk of hypoglycaemia and as such, an early feed is recommended. This study was carried out to ascertain both the impact of an early feed and to establish what type of feeding provided the best option to reduce the risk of hypoglycaemia. The researchers found that infants who were breastfed in the delivery room had a significantly lower rate of borderline hypoglycaemia than those who were not breastfed in the early postpartum period and the researchers concluded that an early breastfeed may facilitate stable blood glucose levels in the infants of mothers with gestational diabetes.

Effects of early breastfeeding on neonatal glucose levels of term infants born to women with gestational diabetes

Results: Eighteen (47%) infants developed hypoglycaemia (blood glucose level less than 2 mmol/L) during the first 2 h of life. There was no difference in the cord blood glucose levels between infants with or without hypoglycaemia (3.7 ± 1.1 vs 4.5 ± 1.1 mmol/L, respectively). Infants of mothers with diabetes diagnosed prior to 28 weeks gestation were at a higher risk of developing hypoglycaemia (8 of 10 vs 10 of 28, OR 7.2, 95%CI 1.3–40.7). Hypoglycaemic infants were of significantly higher birthweight, and were more likely to be born to Caucasian mothers and by Caesarean section. Raised maternal fructosamine blood level, the need for insulin treatment or the infant’s haematocrit were not different between infants with or without hypoglycaemia.

Conclusions: In well-controlled diabetic mothers, the incidence of early hypoglycaemia in infants is still high, particularly in those mothers who had a longer duration of diabetes. Cord blood glucose level did not identify the infants with hypoglycaemia.

Neonatal hypoglycaemia in infants of diabetic mothers

Management of Infants of Diabetic Mothers

The Confidential Enquiry into Maternal and Child Health (CEMACH). Diabetes in pregnancy: caring for the baby after birth. Findings of a National enquiry: England, Wales and Northern Ireland. CEMACH London; 2007

Hypoglycaemia of the Newborn, copy of the literature, from WHO (World Health Organization), with 10 pages of references

Hypoglycemia rates in the first days of life among term infants born to diabetic mothers

Colostrum Versus Formula Supplementation for Glucose Stabilization in Newborns of Diabetic Mothers

Nutritional Factors That Affect the Postnatal Metabolic Adaptation of Full-Term Small- and Large-for-Gestational-Age Infants

Hypoglycemia and the breastfed neonate

Metformin before and during pregnancy and lactation in polycystic ovary syndrome