New Reference Curves on Maternal Weight Gain in Twin Pregnancy

Abstract

Purpose: Aim of the study was to generate reliable weight reference curves on maternal weight gain in twin pregnancy and to compare them to previous studies. Methods: A retrospective mixed model analysis was done at the Obstetric Outpatient Clinic of Zurich University Hospital to evaluate data gathered from 1/2004 to 4/2008. Maternal weight and BMI, before gestation and at the booking visit, as well as the infant birth weight were determined in 245 accurately dateable twin pregnancies of Caucasian women. 5th, 50th and 95th percentiles were presented and simple and multiple regression analyses were performed for various risk factors. Results: Mean weight gain was 19.1 kg at 37 gestational weeks with values of 29.2 kg and 9.1 kg for the 95th and the 5th percentile, respectively. Maternal weight gain at delivery was found to have a significant impact on infant birth weight. If maternal weight gain at delivery increased by 1 kg, then the mean weight of both twins increased by 80 g. Discussion/Conclusions: The presented reference curves on maternal weight gain may be helpful in counseling women with a twin pregnancy -they may reduce the risks arising from low or high maternal weight gain and help to prevent maternal long-term obesity.Zusammenfassung ! Ziele: Erstellung neuer, verlässlicher und leicht anwendbarer Normkurven für die mütterliche Gewichtszunahme in Zwillingsschwangerschaften und Vergleich der Ergebnisse mit Resultaten internationaler Studien. Material und Methoden: Es wurde eine retrospektive Mixed-Model-Analyse durchgeführt, worin Daten der Klinik für Geburtshilfe des Zür-cher Universitätsspitals vom 1/2004 bis 4/2008 ausgewertet wurden. Bei 245 Kaukasierinnen mit genau datierbaren Zwillingsschwangerschaften wurden die mütterliche Gewichtszunahme und BMI, vor der Schwangerschaft und am Termin, sowie die kindlichen Geburtsgewichte bestimmt. Die 5., 50. und 95. Perzentile für die müt-terliche Gewichtszunahme wurden erstellt und simple und multiple Regressionsanalysen für verschiedene Risikofaktoren durchgeführt. Resultate: Die mittlere Gewichtszunahme bei 37 Schwangerschaftswochen lag bei 19,1 kg mit Werten von 29,2 und 9,1 kg für die 95. bzw. 5. Perzentile. Die mütterliche Gewichtszunahme bei Geburt zeigte einen signifikanten Einfluss auf das kindliche Geburtsgewicht. Sobald die mütterliche Gewichtszunahme um 1 kg anstieg, erhöhte sich das mittlere Gewicht beider Zwillinge um 80 g. Schlussfolgerungen: Die präsentierten Normkurven für die mütterliche Gewichtszunahme kön-nen ein hilfreiches Instrument in der Betreuung von Zwillingsschwangerschaften sein -mütter-liche und kindliche Risiken, bedingt durch eine zu geringe oder zu große Gewichtszunahme, kön-nen möglicherweise vermindert und ein nachteiliges "fetal programming" und eine schwangerschaftserworbene Adipositas bei extremen Gewichtszunahmen verhindert werden.

Gestational weight gain in twin pregnancies and maternal and child health: a systematic review

“…Twelve articles reported on GWG and fetal growth, and they consistently demonstrated that after accounting for differences in gestational duration, mothers with twin pregnancies who gained less weight were more likely than those with higher weight gain to deliver infants that were lighter at birth and were more likely to be SGA (20, 24, 27, 28, 36) (Tables 2 and 3). Similar findings were observed in the studies that stratified by prepregnancy BMI (21, 22, 26–28, 30), but results were not always statistically significant due to reduced sample sizes.…”

“…Control for gestational age was performed in 18 of the 25 studies (19–22, 24–30, 32, 33, 35, 36, 38, 42, 45), for prepregnancy BMI in 17 studies (20–24, 26–28, 30, 32, 33, 35, 36, 38, 39, 42, 44, 45) (all of which defined BMI based on recalled prepregnancy weight), chorionicity and/or assisted reproductive technologies in 3 studies (27, 32, 33), and other covariates in 11 studies (20, 22, 24, 27, 32, 36–38, 41, 42, 44). Nine presented results stratified by prepregnancy BMI categories (21, 22, 26–28, 30, 35, 39) (including one which presented results only for normal weight women (27)).…”

“…Nine presented results stratified by prepregnancy BMI categories (21, 22, 26–28, 30, 35, 39) (including one which presented results only for normal weight women (27)). Seventeen studies based their measure of GWG on self-reported prepregnancy weight and a last measured prenatal weight (19, 20, 25–27, 30–33, 35, 38–43, 45), and 9 studied pattern of GWG (19, 25, 30, 32, 35, 37, 38, 41, 42). Half of the studies reported using ultrasound-confirmed gestational age (20, 25–27, 30–33, 37, 38, 43).…”

“…Calculating a rate of total GWG (GWG divided by gestational age) or a rate of weight gain within the first half of pregnancy (<20 weeks or <24 weeks) does not remove the correlation between gestational duration and total weight gain (46). This is because GWG is not linear throughout twin pregnancy (women gain less weight in the first trimester than in the second and third trimester (20)). Limiting to term pregnancies (e.g.…”

“…This approach also results in a highly selective sample because more than half of twin pregnancies are born at <37 weeks (47). Methods recently developed to address the correlation between gestational duration and GWG in singletons, such as maternal weight gain for gestational age z-scores, should be explored in twins (20, 48). …”