Searching for the Definition of Macrosomia through an Outcome-Based Approach

Abstract

BackgroundMacrosomia has been defined in various ways by obstetricians and researchers. The purpose of the present study was to search for a definition of macrosomia through an outcome-based approach.MethodsIn a study of 30,831,694 singleton term live births and 38,053 stillbirths in the U.S. Linked Birth-Infant Death Cohort datasets (1995–2004), we compared the occurrence of stillbirth, neonatal death, and 5-min Apgar score less than four in subgroups of birthweight (4000–4099 g, 4100–4199 g, 4200–4299 g, 4300–4399 g, 4400–4499 g, 4500–4999 g vs. reference group 3500–4000 g) and birthweight percentile for gestational age (90th–94th percentile, 95th-96th, and ≥97th percentile, vs. reference group 75th–90th percentile).ResultsThere was no significant increase in adverse perinatal outcomes until birthweight exceeded the 97th percentile. Weight-specific odds ratios (ORs) elevated substantially to 2 when birthweight exceeded 4500 g in Whites. In Blacks and Hispanics, the aORs exceeded 2 for 5-min Apgar less than four when birthweight exceeded 4300 g. For vaginal deliveries, the aORs of perinatal morbidity and mortality were larger for most of the subgroups, but the patterns remained the same.ConclusionsA birthweight greater than 4500 g in Whites, or 4300 g in Blacks and Hispanics regardless of gestational age is the optimal threshold to define macrosomia. A birthweight greater than the 97th percentile for a given gestational age, irrespective of race is also reasonable to define macrosomia. The former may be more clinically useful and simpler to apply.

A policy of routine umbilical cord blood gas analysis decreased missing samples from high‐risk births

“…Preterm birth, breech birth, abnormal cardiotocography tracings during delivery and small-and large-for-gestational age infants are considered high-risk deliveries and are known risk factors for birth asphyxia (19)(20)(21)(22)(23). The increased risks of missing samples (RR: 3.05-9.07) found in these high-risk deliveries delivered at units practicing selective sampling might have different explanations than not being prepared in emergency situations.…”

“…The final study population comprised 155 235 deliveries of live singleton infants born at 32 completed weeks or later, from 1 January 2008 to 22 October 2014. The final study population comprised 155 235 deliveries of live singleton infants born at 32 completed weeks or later, from 1 January 2008 to 22 October 2014.…”

Excessive weight gain during pregnancy and risk of macrosomia: a meta-analysis

“…Macrosomia is estimated to affect 0.9-12 % of all pregnancies, depending on population characteristics and diagnostic criteria used [1][2][3]. It is associated with a substantially elevated risk of adverse health outcomes for both mothers and offspring.…”

Induction of labour for suspected macrosomia at term in non‐diabetic women: a systematic review and meta‐analysis of randomized controlled trials

“…The common definition of macrosomia is an estimated fetal weight (EFW) of ≥4000 g, which occur in about 1–10% of all pregnancies . Fetal macrosomia is associated with an increased risk of perinatal morbidity and mortality . Intrapartum maternal and perinatal complications include prolonged labour, dystocia, operative vaginal delivery, caesarean delivery, postpartum haemorrhage, vaginal lacerations, shoulder dystocia with brachial palsy, asphyxia as well as facial nerve palsy .…”

“…Fetal macrosomia is associated with an increased risk of perinatal morbidity and mortality . Intrapartum maternal and perinatal complications include prolonged labour, dystocia, operative vaginal delivery, caesarean delivery, postpartum haemorrhage, vaginal lacerations, shoulder dystocia with brachial palsy, asphyxia as well as facial nerve palsy . Routine caesarean delivery for pregnancies with babies suspected to be macrosomic is not uniformly recommended.…”