Gestational diabetes mellitus (GDM) is a condition characterised by impaired glucose tolerance during pregnancy, resulting in hyperglycaemia. GDM affects almost one in five pregnancies in Australia, with more than 280,000 women giving birth each year.¹ While antenatal management appropriately focuses on glycaemic control and obstetric surveillance, GDM is also associated with lower rates of exclusive breastfeeding and shorter breastfeeding duration, highlighting the need for targeted lactation support.² 

Infants born to mothers with GDM are at increased risk of neonatal hypoglycaemia, admission to special care nurseries, and early formula supplementation.³ These risks frequently occur in the context of delayed lactogenesis, maternal-infant separation, and heightened parental anxiety. Antenatal expressing of colostrum has emerged as a strategy that may support early feeding in selected women with GDM when implemented appropriately and safely. 

The Importance of Breastfeeding for Mothers with GDM and Their Infants

Breastfeeding provides important health benefits for all mothers and infants, with particular significance for women with GDM. Women with GDM have a substantially increased lifetime risk of developing type 2 diabetes mellitus (T2DM), with studies demonstrating a nine-to-ten-fold increased risk.^4-5  

Evidence indicates that breastfeeding is associated with a reduced risk of progression to T2DM following GDM, with greater protection seen with longer breastfeeding duration.^4-6 In addition, women with previous GDM who breastfeed for longer periods demonstrate more favourable metabolic profiles, including lower body mass index, reduced fasting glucose and triglyceride levels, and improved insulin sensitivity.^6-8  

For infants exposed to GDM in utero, breastfeeding supports early glucose regulation and has been shown to reduce later risks of obesity and T2DM, highlighting the importance of early and sustained lactation support.^9-10 

Lactation Challenges Associated With GDM 

Women with GDM are more likely to experience delayed lactogenesis II, increasing the likelihood of early supplementation, particularly in the context of neonatal hypoglycaemia protocols.^11-13 Early supplementation may interfere with the establishment of maternal milk production and undermine breastfeeding confidence. 

Women with GDM frequently report low breastfeeding confidence and perceived insufficient milk supply, particularly when supplementation is introduced without concurrent strategies to protect milk production.¹⁴ GDM is also linked to higher rates of complications such as prematurity, caesarean birth, macrosomia, and neonatal hypoglycaemia, which may lead to maternal-infant separation, delayed breastfeeding initiation, and reduced opportunities for early skin-to-skin contact.^13,15 

Preparing to Breastfeed With GDM

Optimising breastfeeding outcomes for women with GDM requires proactive, anticipatory care.  

Early initiation of breastfeeding, ideally within the first hour after birth, and frequent feeding thereafter supports milk production and neonatal glucose regulation. When direct breastfeeding is delayed, early hand expression is important to maintain breast stimulation and provide nutrition. Skin-to-skin contact supports thermoregulation, glucose stability, feeding behaviours, and bonding.¹⁶  

Antenatal Expressing: Rationale and Potential Benefits

Antenatal expressing involves the expression of colostrum during late pregnancy, most commonly from 36 weeks’ gestation in low-risk pregnancies.¹⁷ The aim is not to stimulate milk production antenatally, but to collect small volumes of colostrum for potential use in the early postnatal period. 

For women with GDM, stored colostrum may be used to support early feeding if the infant experiences hypoglycaemia, requires supplementation, or if effective breastfeeding is delayed.¹⁸ Access to expressed colostrum may reduce reliance on formula supplementation in the immediate postnatal period. 

Antenatal expressing may also improve familiarity with hand expression and support early milk removal after birth. Expressed volumes during pregnancy are typically small and variable, and the absence of antenatally expressed colostrum does not predict breastfeeding success. Importantly, antenatal expressing has not been shown to accelerate the onset of lactation in women with diabetes in pregnancy.¹⁸ 

Practical Guidance for Antenatal Expressing

When to Commence

For women with uncomplicated GDM, antenatal expressing may be considered from 36 weeks’ gestation.^17,18 Earlier commencement is not recommended due to concerns regarding uterine stimulation and preterm labour. 

How to Express

Hand expression is preferred antenatally due to the small volume and thick consistency of colostrum. Expressing once or twice daily for a few minutes per breast may be suggested, stopping if discomfort or uterine tightening occurs. 

Expected Volumes 

Clear education about normal expectations is essential. Drops or small syringe volumes are sufficient, and some women may not express any colostrum antenatally. This variation is normal. 

Storage and Transport

Colostrum should be collected in sterile syringes, clearly labelled, frozen, and transported to hospital in accordance with local health service protocols. 

Safety Considerations and Contraindications

Although evidence suggests that antenatal expressing from 36 weeks’ gestation is safe in low-risk pregnancies, careful screening is required. Antenatal expressing is not recommended where there is risk of preterm labour, placenta praevia, unexplained bleeding, or other contraindications to nipple stimulation.¹⁸ Women should stop and seek review if they experience contractions, bleeding, or reduced fetal movements. Antenatal expressing should remain optional, with reassurance and a woman-centred approach. 

 Key Messages

• Neonates born to women with GDM have increased risks of hypoglycaemia and feeding challenges, alongside lower rates of exclusive breastfeeding.

• Breastfeeding provides important short and long-term metabolic benefits for both mothers with GDM and their infants.

• Antenatal expressing of colostrum may be considered from 36 weeks’ gestation for selected women with uncomplicated GDM.

• Hand expressing is preferred antenatally, with clear education about normal variability in colostrum volumes.

• Antenatal expressing should be offered as an option, not an expectation, and absence of expressed colostrum does not predict breastfeeding success.

• Careful screening for contraindications and multidisciplinary communication is essential for safe implementation.