Impact of maternal body build characteristics on newborn size in two different European populations

SYLVIA KIRCHENGAST, BEDA HARTMANN, KARL W. SCHWEPPE,3 AND PETER HUSSLEIN4

Abstract The association patterns between maternal anthropometric characteristics (stature, prepregnancy weight, prepregnancy body mass index, pregnancy weight gain) and newborn size (birth weight, length, head circumference) were tested with 10,240 single births taking place between 1985 and 1995 in Vienna, Austria, and 3,452 single births taking place between 1989 and 1995 in Westerstede-Ammerland (Friesland), northern Germany. Maternal size and newborn size differed highly significantly (p

KEY WORDS: MATERNAL ANTHROPOMETRICS, PREPREGNANCY WEIGHT, PREGNANCY WEIGHT GAIN, BIRTH WEIGHT, NEWBORN SIZE

Newborn size is an important factor in determining the survivorship of infants within the first months of their life and thus is a major factor for the reproductive success of individuals and populations. Most of the research on this subject has been done in the recent past, and especially population groups of contemporary developing societies in Africa, Asia, Central America, and South America were considered (Tanner 1981; Wiley 1994). Nevertheless, questions regarding newborn size and its influence on perinatal and infant mortality and morbidity also gain importance in developed countries such as those in Western Europe and the United States.

The size of newborn infants is affected by several environmental and genetic factors. Although maternal and family factors are substantial for newborn size, their influence is not overwhelming. The mother-offspring and sibsib relationships yielded correlations in the range of 0.15-0.30 (Livshits 1986; Rao et al. 1975; Ounsted et al. 1982). Besides exogenous factors such as socioeconomic conditions and maternal smoking behavior (Ward and Ward 1984; Ward 1987; Wen et al. 1990; Adair and Bisgrove 1991), gestational age, maternal age, height, and weight influence newborn size (Frisancho et al. 1983; Garn and Pesick 1982; Martorell and Gonzalez-Cossio 1987). It is well documented that taller women tend to gave birth to larger babies than shorter women and that heavier mothers tend to have heavier offspring than more slender mothers of comparable height (Niswander and Gordon 1972). Although this relationship between maternal body size and mass and newborn size has been known for several decades, only during the last two decades has its importance to the outcome of pregnancy been properly recognized (Rosso 1985). Furthermore, maternal body size indicates environmental conditions as well as genetic factors. Maternal stature especially reflects the genetic potential of the mother, but it can be an indicator of nutritional history of the mother. Therefore stature reflects both environmental and genetic conditions of the mothers. Especially in poorly nourished populations, such as those in developing countries, short maternal stature is likely to be the result of poor nutritional history and not an adequate reflection of the maternal and consequently the infant genotype. Maternal prepregnancy weight is mostly significantly correlated with maternal height and reflects the genetic potential for growth; however, it is also a major indicator for the actual environmental conditions of the mother (Adair and Bisgrove 1991). Besides stature and prepregnancy weight, the nearly exclusively environmentally determined weight gain during pregnancy plays an important role in determining birth weight and may affect infant morbidity and mortality.

The present study focuses on the relations between maternal somatometric parameters, such as prepregnancy body weight and height and pregnancy weight gain, and newborn size in two European populations (Viennese and northern Germans).

Materials and Methods

Subjects. Our study is based on two data sets: (1) 10,240 single births taking place between 1985 and 1995 at the II University Clinic for Gynecology and Obstetrics in Vienna, Austria, and (2) 3,452 single births taking place between 1989 and 1995 at the Clinic for Gynecology and Obstetrics of Westerstede-Ammerland (Friesland), Germany. All probands were white; however, they belong to completely different population groups. The Viennese women exclusively originated from Austria or other countries of central Europe. Nearly all of them lived in Vienna (population 1.7 million inhabitants) or in Viennese suburban areas in the neighboring Lower Austria. All women participating in the present study belong to the urban social middle class. Westerstede-Ammerland is a relatively small town (127,000 inhabitants) in northern Germany about 50 km northwest of Bremen. The women stemmed exclusively from small villages of the agricultural areas surrounding Westerstede-Ammerland (within 30 km) and belong to the Frisian population of northern Germany.

All births occurred between 39 and 41 weeks of gestation. Women with coincident medical disease (e.g., diabetes mellitus, drug addiction) or who had twins were excluded from the present study. The births were either the first or the second for all women. The Viennese women ranged in age from 18 to 42 years (x = 28.2 yr; SD = 5.7); the women from WesterstedeAmmerland ranged in age from 19 to 42 years (x = 28.4 yr; SD = 4.8).