Table 3 Included studies on maternal obesity and delayed onset of lactation

Chapman & Perez-Escamilla 1999 [15] USA 1996–1997

Hartford Hospital, Connecticut Healthy, single, term infant n = 192

Women's bodies were classified as slim, average, heavy or obese

Delayed lactogenesis (> 72 hours)

Slim/average build 26.4%

Heavy/obese build 52.2%

Multivariate analysis

Heavy/obese build OR 3.2 (95 CI% 1.5, 6.7)

(adjusted for birth weight, method of birth, ethnicity, serious medical condition, parity, formula feeding day 2)

Chapman & Perez-Escamilla 2000 [46] USA 1997–1998

Connecticut Healthy mothers with a healthy, single, term infant n = 57

Definition of obesity: at least 2 of 3:

1. BMI at 72 h > 30,

2. subscapular skin fold thickness at 72 h > 33.7 mm (> 85%ile)

3. heavy/obese build on day 1.

Multivariate analysis

Onset -Milk transfer at 60 h (< or > 9.2 g/feed)

Obese: OR 6.14 (95%CI: 1.10, 37.41, p = 0.05) compared to non-obese

Onset – Maternal perception (< or > 72 h)

Obese: OR 1.97 (95%CI: 0.29, 13.41, p = 0.49) compared to non-obese

Non-obese:

Women who bf more frequently had higher milk transfer values and earlier onset of lactogenesis, than women who bf less frequently

Obese:

No relationship between these variables

Dewey et al 2003 [47] USA 1999

Davis, California Healthy, single, term infants, planning to bf > 1 m n = 280

BMI measured 2 weeks postpartum BMI > 27.0 taken as overweight/obese

Delayed lactogenesis (> 72 hours)

Normal 16%

Overweight/obese 33%

p < 0.05

Multivariate analysis for delayed lactogenesis:

Overweight/obese: RR 2.46 (95%CI: 1.45, 3.64)

(adjusted for C-section, parity, flat nipples, birth weight):

Multivariate analysis for suboptimal infant feeding behaviour on day 7:

Overweight/obese: RR 2.58 (95%CI: 1.07, 5.22).

Hilson et al 2004 [42] USA 1998

Bassett Hospital, Cooperstown, NY Intended to bf, singleton infant n = 114

BMI calculated from pre-pregnancy weight and height

IOM definition of obesity

Delayed lactogenesis (> 72 hours)

Normal 18.5%

Overweight 30.8%

Obese 33.3%

Univariate analysis NS

Multivariate analysis NS {not enough power to show a difference}

Rasmussen et al 2004 [16] USA Years of study not stated

Bassett Healthcare, Cooperstown, NY n = 40

Pre-pregnancy BMI from medical records

IOM definition of obesity

Duration of feed at 7 days postpartum:

Overweight/obese women: infants fed for longer: 23.2 (sd 5.6) mins, compared to 15.3 (sd 6.1) mins for normal weight women (p < 0.005)

Prolactin response to suckling (ng/ml):

48 hours

Normal women 26.0 (sd 61.5)

Overweight/obese women -10.3 (sd 28.3)

p < 0.05

Prolactin response to suckling (ng/ml):

7 days

Normal women 80.9 (sd 67.6)

Overweight/obese women 57.1 (sd 60.2)

NS

Other hormones (insulin, estradiol, progesterone): NS difference between groups. However, insulin levels were 44% higher in overweight/obese women at 7 days (non-fasting levels and inadequate power).

Path analysis: effect of pre-pregnant BMI on prolactin response at 7 days: -30.9 ng/ml.