**1. Introduction**

26 From Preconception to Postpartum

Zeldow, P. & Daugherty, S. (1991). Personality profiles and specialty choices of students

Zuckerman, M., Navizedeh, N., Feldman, J. et al. (2002). Determinants of woman's choice of

Obstetrician/Gynecologist. *J Women's Health & Gender-Based Medicine*, vol. 11, pp.

from two medical school classes. *Acad Med*, vol. 66, pp. 283-287.

175-180.

Birth weight is an important predictor in infant mortality and morbidity, growth, development and wellbeing in adult life (Goldfrey & Barker, 2000). Reduced-size-at-birth infants, which include low birth weight (LBW: birth weight <2,500 g) and small-forgestational age (SGA: below the 10th percentile for gestational age) infants, are at greater risk of having reduced educational capacity, school performance, and intellectual development than are infants of normal birth weight (Lagerstrom et al., 1991).

Some adult health risks also have a clear negative correlation with infant birth weight. In 1980', Barker & Osmond in the UK reported that differences around the UK in neonatal mortality as maker for LBW in 1921-1925 predicted death rates from stroke and heart disease in 1968-1978 (Barker & Osmond, 1986). They found that LBW and weight at one year were associated with an increased risk of death from cardiovascular disease. There was an approximate two times of the mortality rate from the highest to the lowest extremes of birth weight (Barker et al., 1989).

Over recent decades, accumulating evidence around the world has suggested that LBW may be associated with an increased risk of subsequent development of a variety of complications in adulthood including cardiovascular disease, non-insulin-dependent diabetes mellitus, hypertension, and dyslipidemia (Li et al., 1998; Rich-Edwards et al., 1999). These studies have led to discoveries of the developmental, fetal origins of adult health and disease; fetal programming theory states that fetal growth restriction, secondary to under nutrition, has long-lasting physiologic and structural effects that predispose the fetus to diseases later in life.

On the other hand, high birth weight relates to complications during delivery including shoulder dystocia and caesarean sections and to obesity during child- and adulthood (Stotland et al., 2004; Weiss et al., 2004). Increased numbers of high birth weight infants (>4,000 g) and large-for-gestational age infants (LGA; birth weight above the 90th percentile for gestational age) have been reported in North America and Europe (Kramer et al., 2002; Surkan et al., 2004). In the past three decades, there has been a 116 g increase in singleton birth weight (Catalano, 2007). Fetal growth is affected by maternal obesity and by mothers being overweight during pregnancy. Recent evidence suggests that LGA infants are also at increased risk for childhood and subsequent adult obesity as well as type two diabetes (Parsons et al., 2001). Thus, birth weight may be an important parameter of adult disease.

The Effect of Prepregnancy Body Mass Index and Gestational Weight Gain on Birth Weight 29

increasing birth weight. In the regression model, the low optimal birth weight at 40 weeks' gestation was 2,982 g (95% confidence interval (CI): 2,965-2,999 g) for females and 3,012 g (95% CI: 3,008-3,018 g) for males. Similarly, the high end of optimal birth weight range was 3,813 g (95% CI: 3,774-3,852 g) for females and 3,978 g (95% CI: 3,976-3,980 g) for males.

Fig. 1. Birth weight specific rates of serious neonatal morbidity and neonatal mortality at 37

The optimal birth weight range may vary according to the age, race, ethnicity, and size of the mother, as maternal growth constraint may protect the health of the mother and baby. A study of 16.4 million women using the National Center for Health Statistics' 1983-1987 national lived birth/infant death data sets, examined the association between birth weight and neonatal mortality rate in adolescent (aged 15-18 years) and adult mothers (aged 19-34 years) of black and white race. Minimum neonatal mortality rates occurred at the same birth weight (3,500 to 4,499 g white and 3,000 to 3,999 g black) whether mothers of the infants were adolescents or adults. The most favorable range of birth weight, in which survival was greatest, commenced at 3,000 g for all mothers and terminated at 3,999 g for most black adolescents and black adults, at 4,499 g for most white adolescents, and at 4,999 g for white adults. Of infants born to mothers < or = 16 years old, 33% were lighter and 1.5% were heavier than the favorable birth weight range (Rees et al., 1996). Assisting mothers to bear infants with birth weight in the optimal weight range corresponding with low neonatal

Adequate weight gain by prepregnancy BMI is important for optimal pregnancy outcomes. The Institute of Medicine (IOM) released new gestational weight guidelines (IOM, 2009) to reinforce those released in 1990 (IOM, 1990), because many key aspects of the health of women of childbearing age have changed, such as the increasingly high rates of overweight and obese women, increasing GWG, and the increasing age of women becoming pregnant. There are several salient differences. First, the new guidelines change the BMI categories to those commonly used for other adult health outcomes. Second, they provide a closed gestational weight gain range for obese women, based on data from women with BMI

mortality in each country is an appropriate goal of clinical management.

Source; Reference [Joseph KS., et al.,2009]

weeks' gestational age among singletons

**3. Optimal weight gain recommendation** 

values of 30-34.9 kg/m2.

Numerous factors are associated with birth weight, such as parity and the sex of the child (Bonellie et al., 2008), maternal and gestational diabetes (Langer et al., 2005), maternal smoking during pregnancy (Ward et al., 2007), maternal overweight status (Larsen et al., 1990), and gestational weight gain (GWG) (Kiel et al., 2007). Of these factors, previous studies have suggested particularly that both prepregnancy body mass index (BMI; weight (kg)/ height (m) 2) and GWG are positively associated with birth weight in the offspring and are related to risks of both low and high offspring birth weight (Brown et al., 2002; Rode et al., 2007). Women with a normal prepregnancy BMI and those who meet the recommended weight gains are healthiest and have healthier children. Adequate GWG contributes to better pregnancy outcomes in both mothers and infants, for short- and long-term health. Prepregnancy BMI and GWG management may be a key factor influencing the health of women during pregnancy and the development of the fetus. This review focuses on the effect of prepregnancy BMI and adequate GWG on birth weight.
