Macrosomic and low birth weight neonates in Pacific Islanders from Samoa: a case-control study

To assess the perinatal morbidity and mortality of macrosomic (>4500 g) and low birth weight (LBW) (<2500 g) neonates in a Pacific Islander population (PIP) from Samoa compared to a Caucasian population (CP).

Case-control study. Clinical data were extracted by chart review.

In 3166 (PIP) and 2101 (CP) deliveries, macrosomia was more prevalent and LBW less prevalent in the PIP [76/3166 (2.4 %) vs. 21/2101 (0.9 %); p < 0.0001 and 149/3166 (4.7 %) vs. 163/2101 (7.7 %); p < 0.0001, respectively]. Among macrosomic neonates, perinatal mortality and composite severe neonatal morbidity (CNM) were higher in the PIP compared to the CP [2/76 (3 %) vs. 0/21 (0 %) and 6/76 (7 %) vs. 1/21 (4 %), respectively]. Among LBW neonates, mortality, but not CNM, was significantly higher in the PIP [16/149 (7 %) vs. 2/163 (1 %), p < 0.0001 and 10/149 (6 %) vs. 5/163 (3 %), p = 0.2, respectively]. The proportion of macrosomic neonates transferred to the Neonatal Intensive Care Unit was significantly higher in the PIP [50/76 (65 %) vs. 0/21 (0 %), p < 0.0001]. Age, body mass index, and delivery mode did not independently predict CNM.

Samoan women have higher rates of macrosomia and lower rates of LBW compared to Caucasians, suggesting an anthropomorphic basis of this phenomenon.