The prospective associations of fetal growth-related pregnancy complications with subsequent breastfeeding duration and markers of human milk production.

BACKGROUND

The development of the breast for lactation occurs throughout pregnancy. It is unknown whether pregnancy complications resulting in poor fetal growth can affect breastfeeding (BF) success.

OBJECTIVES

We examined whether fetal growth-related pregnancy complications were associated with earlier BF cessation and changes in the concentrations of human milk biomarkers of low milk production.

METHODS

We used data from the Growing Up in Singapore Toward healthy Outcomes study (n = 954). Human milk concentrations of protein, lactose, citrate, sodium, potassium, and zinc at 3 wk postpartum were available for 180 mother-infant dyads. We examined the associations of fetal growth measures, including term infants born small-for-gestational-age (SGA) (<10th percentile), pregnancies complicated by fetal growth deceleration (second to third trimester fetal growth dropped between major centiles), elevated umbilical artery resistance (>90th percentile) or hypertensive disorders of pregnancy (HDP) with 1) risk of ceasing BF (Cox regression) and 2) concentrations of human milk components (weighted linear regression).

RESULTS

Adjusting for maternal education, smoking exposure, BF intentions, and prepregnancy BMI (in kg/m2), individuals who delivered SGA infants and those with HDP were more likely to breastfeed for a shorter duration when compared to those with uncomplicated pregnancies {adjusted hazard ratio [95% confidence interval (CI)]: 1.45 (1.11, 1.89) and 1.61 (1.14, 2.29), respectively}; associations were nonsignificant for fetal growth deceleration and umbilical artery resistance. SGA was not associated with concentrations of human milk biomarkers, but compared to participants with uncomplicated pregnancies, milk produced by those with HDP contained lower zinc concentrations [adjusted β coefficient (95% CI): -0.56 mg/L (-1.08, -0.04) mg/L].

CONCLUSIONS

Individuals with HDP and those with SGA infants tend to breastfeed for a shorter duration; however, only HDP appear to be associated with biomarkers of compromised milk production. Further research and support are needed to help individuals with HDP and SGA achieve their BF goals. This trial was registered at clinicaltrials.gov as NCT01174875.