Critical periods of maternal weight gain: effect on twin birth weight

A new care pathway to optimize gestational weight gain in twin pregnancies

BACKGROUND

Maternal gestational weight gain is an important determinant of pregnancy outcomes and may have an even greater role in twin pregnancies because of their higher rate of pregnancy complications and greater nutritional demands. However, data on the optimal week-specific gestational weight gain in twin pregnancies and on interventions that should be applied in cases of inadequate gestational weight gain are limited.

OBJECTIVE

This study aimed to determine whether a new care pathway that involves monitoring gestational weight gain using a week-specific chart, along with a standardized protocol for managing cases with inadequate gestational weight gain, can optimize maternal gestational weight gain in twin pregnancies.

METHODS

In this study, patients with twin pregnancies followed in a single tertiary center between February 2021 and May 2022 were exposed to the new care pathway (postintervention group). Gestational weight gain and clinical outcomes were compared with those of a previously described cohort of patients with twins followed in our clinic before the implementation of the new care pathway (preintervention group). The new care pathway targeted patients and care providers and included educational material, a newly developed body mass index group-specific gestational weight gain chart, and a stepwise management algorithm in cases of inadequate gestational weight gain. The body mass index group-specific gestational weight gain charts were divided into 3 zones: (1) green zone (optimal gestational weight gain at 25th-75th centiles); (2) yellow zone (suboptimal gestational weight gain at 5th-24th or 76th-95th centiles); and (3) gray zone (abnormal gestational weight gain, at <5th or >95th centile). The primary outcome was the overall proportion of patients achieving optimal gestational weight gain at birth.

RESULTS

A total of 123 patients were exposed to the new care pathway and were compared with 1079 patients from the preintervention period. Patients in the postintervention group were more likely to achieve optimal gestational weight gain at birth (60.2% vs 47.7%; adjusted odds ratio, 1.91; 95% confidence interval, 1.28-2.86) and were less likely to achieve low-suboptimal gestational weight gain (7.3% vs 14.7%; adjusted odds ratio, 0.41; 95% confidence interval, 0.20-0.85) or any suboptimal gestational weight gain (26.8% vs 34.8%; adjusted odds ratio, 0.60; 95% confidence interval, 0.39-0.93) at birth. In addition, patients in the postintervention group were less likely to have low-abnormal gestational weight gain anytime during gestation (18.9% vs 29.1%; P=.017) and were more likely to have normal gestational weight gain throughout pregnancy (21.3% vs 14.0%; P=.031) or high-abnormal gestational weight gain anytime during gestation (18.0% vs 11.1%; P=.025), suggesting that in comparison with standard care, the new care pathway is more effective in preventing patients from moving into the low-abnormal zone than the high-abnormal zone. Furthermore, the new care pathway was more effective than standard care in correcting high-suboptimal gestational weight gain and high-abnormal gestational weight gain.

CONCLUSION

Our findings suggest that the new care pathway may be effective in optimizing maternal gestational weight gain in twin gestations, which may in turn contribute to better clinical outcomes. This is a simple, low-cost intervention that can be easily disseminated among providers caring for patients with twin pregnancies.

Early Gestational Weight Gain and the Risk of Preeclampsia in Dichorionic Twin Pregnancies

OBJECTIVE

The purpose of our study was to evaluate the body mass index (BMI)-specific association between early gestational weight gain (GWG) in dichorionic twin pregnancies and the risk of preeclampsia.

STUDY DESIGN

We conducted a retrospective cohort study of all dichorionic twin pregnancies from 1998 to 2013. Data were obtained from a perinatal database and chart abstraction. Prepregnancy BMI was categorized as normal (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (≥30 kg/m2). Early GWG was defined as the last measured weight from 160/7 to 196/7weeks' gestation minus prepregnancy weight. GWG was standardized for gestational duration using BMI-specific z-score charts for dichorionic pregnancies. Preeclampsia was diagnosed using American College of Obstetricians and Gynecologists criteria and identified with International Classification of Diseases-9 coding. Early GWG z-score was modeled as a three-level categorical variable (≤ - 1 standard deviation [SD], 0, 3 +1 SD), where -1 to +1 was the referent group. We estimated risk differences and 95% confidence intervals (CIs) via marginal standardization.

RESULTS

We included 1,693 dichorionic twin pregnancies in the cohort. In adjusted analysis, the incidence of preeclampsia increased with increasing early GWG among women with normal BMI. Women with normal BMI and a GWG z-score < - 1 (equivalent to 2.6 kg by 20 weeks) had 2.5 fewer cases of preeclampsia per 100 births (95% CI: -4.7 to - 0.3) compared with the referent; those with GWG z-score > +1 (equivalent to gaining 9.8 kg by 20 weeks) had 2.8 more cases of preeclampsia per 100 (95 % CI: 0.1-5.5) compared with the referent. In adjusted analyses, early GWG had minimal impact on the risk of preeclampsia in women with overweight or obesity.

CONCLUSION

GWG of 2.6 kg or less by 20 weeks was associated with a decreased risk of preeclampsia among women pregnant with dichorionic twins and normal prepregnancy BMI. Current GWG guidelines focus on optimizing fetal weight and gestational length. Our findings demonstrate the importance of considering other outcomes when making GWG recommendations for twin pregnancy.

KEY POINTS

· Early GWG decreased with increasing BMI category.. · Among women with normal weight, as early GWG increased so did the risk of preeclampsia.. · There was no association between early GWG and preeclampsia among women with overweight or obesity..

Correlation between Maternal Weight Gain in Each Trimester and Fetal Growth According to Pre-Pregnancy Maternal Body Mass Index in Twin Pregnancies

Background andObjectives: This study aimed to determine the correlation between maternal weight gain in each trimester and fetal growth according to pre-pregnancy maternal body mass index in twin pregnancies. Materials and Methods: We conducted a retrospective review of the medical records of 500 twin pregnancies delivered at 28 weeks’ gestation or greater at a single tertiary center between January 2011 and December 2020. We measured the height, pre-pregnant body weight, and maternal body weight of women with twin pregnancies and evaluated the relationship between the maternal weight gain at each trimester and fetal growth restriction according to pre-pregnancy body mass index. Results: The overweight pregnant women were older than the normal or underweight pregnant women, and the risk of gestational diabetes was higher. The underweight pregnant women were younger, and the incidence of preterm labor and short cervical length during pregnancy was higher in the younger group. In normal weight pregnant women, newborn babies’ weight was heavier when their mothers gained weight, especially when they gained weight in the second trimester. Mothers’ weight gain in the first trimester was not a significant factor to predict fetal growth. The most predictive single factor for the prediction of small neonates was weight gain during 24−28 and 15−18 weeks, and the cutoff value was 6.2 kg (area under the curve 0.592, p < 0.001). Conclusions: In twin pregnancy, regardless of the pre-pregnant body mass index, maternal weight gain affected fetal growth. Furthermore, weight gain in the second trimester of pregnancy is considered a powerful indicator of fetal growth, especially in normal weight pregnancies.

The Association between Gestational Weight Gain in Each Trimester and Pregnancy Outcomes in Twin Pregnancies

OBJECTIVE

Adequate maternal weight gain in twin pregnancies is associated with improved outcomes such as increased fetal growth and decreased incidence of preterm birth. However, it remains unclear when gestational weight gain has the greatest influence on pregnancy outcomes. Our objective was to identify at which time in a twin pregnancy does inadequate maternal weight gain have the greatest association with adverse pregnancy outcomes.

STUDY DESIGN

This is a retrospective cohort study of women with twin pregnancies and normal prepregnancy body mass index (BMI, 18.5-24.9 kg/m²) who delivered at ≥24 weeks' gestation by a single maternal-fetal medicine practice between 2005 and 2017. Baseline characteristics and pregnancy outcomes were compared between women with and without adequate average gestational weight gain (weight gain per week based on the 2009 Institute of Medicine recommendations). This analysis was performed for weight gain over the entire pregnancy, as well as from 0 to 16, 16 to 24, and 24 weeks to delivery. Multivariable regression analysis was performed to control for potential confounding variables.

RESULTS

A total of 609 women with twin pregnancies and normal prepregnancy BMI were included, of whom 386 (63.4%) had adequate average gestational weight gain over the entire pregnancy and 223 (36.6%) did not. Inadequate average gestational weight gain between 0 and 16 weeks' gestation was associated with a higher incidence of birthweight less than the 10th percentile for gestational age (adjusted odds ratio [aOR]: 1.67; 95% confidence interval [CI]: 1.11-2.51) and less than the 5th percentile for gestational age (aOR: 2.10; 95% CI: 1.29-3.40). Inadequate gestational weight gain between 16 and 24 weeks was associated with lower birthweight of the larger twin (β: -0.09; p = 0.04). Inadequate weight gain from 24 weeks to delivery was associated with spontaneous preterm birth <37 weeks' gestation (aOR: 1.67; 95% CI: 1.13-2.47), <34 weeks' gestation (aOR: 4.32; 95% CI: 2.45-7.63), <32 weeks' gestation (aOR: 9.07; 95% CI: 3.66-22.48), and a lower incidence of preeclampsia (aOR: 0.31; 95% CI: 0.16-0.63).

CONCLUSION

In twin pregnancies, gestational weight gain between 0 and 16 weeks as well as between 16 and 24 weeks is most associated with fetal growth, whereas gestational weight gain after 24 weeks is most associated with preterm birth. This may help elucidate the mechanism of action of the impact of gestational weight gain in twin pregnancies.

Gestational weight gain charts for twin pregnancies in Southeast China

Background

To establish age-standardized charts of weight gain for term twin pregnancies in Southeast China.

Methods

We designed a retrospective study on data from women pregnant with twins, a gestational age beyond 36 weeks and an average weight ≥ 2500 g. We established hierarchical linear regression models to express gestational weight gain patterns.

Results

We analyzed data from 884 women pregnant with twins (151 underweight, 597 normal weight, and 136 overweight). Our final models fit the crude weight measurement data well. The means of weight gain generally decreased as the pre-pregnancy BMI increased. For each BMI category, the mean weight gains increased with the gestational age and the standard deviation increased slightly. The mean weight gains were 18.82 ± 6.73, 18.53 ± 6.74, and 16.97 ± 6.95 kg at 37 weeks in underweight, normal weight, and overweight women, respectively.

Conclusion

The weight gain chart can be used to estimate maternal weight gain to be gestational age–standardized z scores by pre-pregnancy BMI and may serve as an innovative tool for perinatal care providers to guide the weight gain of women pregnant with twins.

Weight gain and pregnancy outcomes in overweight or obese women with twin gestations

BACKGROUND

While adequate weight gain in twin pregnancies with normal prepregnancy BMI has been associated with improved pregnancy outcomes, it remains unclear whether adequate weight gain in patients with overweight or obese prepregnancy BMI is associated with similarly improved pregnancy outcomes, and whether this comes at the expense of maternal health risks such as increased risk for gestational diabetes or hypertension.

OBJECTIVE

To estimate the association between adherence to weight gain recommendations and pregnancy outcomes in overweight and obese women with twin pregnancies.

METHODS

This is a retrospective cohort study of women with overweight (BMI 25.0-29.9 kg/m²) and obese prepregnancy BMI (≥30.0 kg/m²) and twin pregnancies delivered >24 weeks by a single MFM practice between 2005 and 2017. Baseline characteristics, weight gain patterns, and pregnancy outcomes were compared between women who met or exceeded, and who did not meet gestational weight gain requirements, as recommended by the Institute of Medicine (IOM) in 2009. Since total weight gain is also dependent on gestational age at delivery, we used weight gain per week to define adequate weight gain for overweight (0.85 lb/week) and obese (0.68 lb/week) women.

RESULTS

A total of 252 overweight and obese women with twin pregnancies met inclusion criteria, 171 (67.9%) of whom met or exceeded weight gain requirements and 81 (32.1%) of whom did not. There were no differences in baseline clinical and demographic characteristics between the two groups. Women with inadequate weight gain had significantly less weight gain in each trimester, as well as less total weight gain for the whole pregnancy. Women with inadequate average gestational weight gain had significantly lower birthweights of the larger twin (2440 versus 2675 g, p = .001) and the smaller twin (2212 versus 2398 g, p = .005), higher incidence of spontaneous preterm birth <37 weeks (33.3 versus 21.1%, p = .03), higher incidence of premature rupture of membranes (24.7 versus 11.7%, p = .008), and greater likelihood of any twin birthweight < 10th percentile for gestational age (51.9 versus 35.5%, p = .01). There were no differences in the likelihood of cesarean delivery, preeclampsia, or gestational diabetes between the two groups. These results did not differ after excluding the 24 women in the cohort with excessive weight gain.

CONCLUSIONS

For overweight and obese women with twin gestations, meeting the IOM recommendations for weight gain in pregnancy is associated with improved pregnancy outcomes. CondensationWomen with overweight or obese prepregnancy BMI in twin gestations who gain the recommended amount of weight in pregnancy have improved pregnancy outcomes.

Weight gain and pregnancy outcomes in underweight women with twin gestations

Background: Adherence to minimum weight gain recommendations in twin pregnancies as defined by the Institute of Medicine (IOM) guidelines is associated with improved pregnancy outcomes; however, these recommendations have yet to be made for underweight women (BMI < 18.5 kg/m²).Objective: To determine if existing pregnancy weight gain recommendations in twin gestations apply to women with underweight prepregnancy body mass index (BMI), and if these women have similar pregnancy outcomes to women with normal prepregnancy BMI.Methods: This is a retrospective cohort study of women with underweight (BMI < 18.5 kg/m²) and normal prepregnancy BMI (18.5-24.9 kg/m²) and twin pregnancies delivered > 24 weeks by a single Maternal Fetal Medicine (MFM) practice between 2005-2017. Weight gain patterns and pregnancy outcomes were compared between women with underweight prepregnancy BMI and normal prepregnancy BMI. The primary outcomes of the study were gestational age at delivery and intrauterine growth restriction.Results: A total of 664 women met inclusion criteria during the study period, 55 (8.3%) of whom had an underweight prepregnancy BMI, and 609 (91.7%) of whom had a normal prepregnancy BMI. There were no differences in baseline clinical and demographic characteristics between the groups, nor any differences in overall weight gain or weight gain patterns between the two groups. There were no significant differences between the groups in birthweight of the larger twin (2415 versus 2489 g, p = .26) or the smaller twin (2150 versus 2190 g, p = .55), gestational age at delivery (35.8 versus 35.8 weeks, p = .96), incidence of preterm birth < 34 weeks (16.4 versus 16.3%, p = .98), spontaneous preterm birth < 34 weeks (9.1 versus 11.7%, p = .57), or the incidence of either twin with a birthweight < 10% for gestational age (60.0 versus 56.0%, p = .57) or < 5% for gestational age (36.4 versus 30.9%, p = .40).Conclusions: Women with underweight prepregnancy BMI who gain equal weight to women with normal prepregnancy BMI have similar pregnancy outcomes. The recommendations for adequate weight gain in women with underweight prepregnancy BMI should therefore not exceed those for women with normal prepregnancy BMI.

Gestational Weight Gain per Pre-Pregnancy Body Mass Index and Birth Weight in Twin Pregnancies: A Cohort Study in Wuhan, China

To assess the relationship between gestational weight gain (GWG) of twin-pregnancy women and twin birth weights, as well as to evaluate whether pre-pregnancy body mass index (BMI) influences this relationship. A cohort study was conducted in Wuhan, China, between 1/01/2011 and 8/31/2017. Women with twin pregnancies who delivered live and non-malformed twins were included (6,925 women and 13,850 infants), based on the Wuhan Maternal and Child Health Management Information System. Logistic regression models were employed to examine the association between GWG and paired small for gestational age (SGA, defined as birth weight <10th percentile for gestational age and sex)/SGA and linear regression models were utilized to explore the relationship between GWG and sum of birth weights. The associations of GWG based on both the IOM and Chinese recommendations and SGA/SGA pairs were obtained, as well as the stratified analyses by pre-pregnancy BMI. Additionally, the sum birth weight of one twin pair increased by 15.88 g when the GWG increased by 1 kg. GWG below the IOM and Chinese recommendations was associated with an increased risk of SGA/SGA pairs in all pre-pregnancy BMI categories. However, in underweight, overweight, and obese women, the association between GWG above the IOM and Chinese recommendations and SGA/SGA pairs changed with adjustment.

Influence of weight gain, according to Institute of Medicine 2009 recommendation, on spontaneous preterm delivery in twin pregnancies

Backgrounds

Maternal total weight gain during pregnancy influences adverse obstetric outcomes in singleton pregnancies. However, its impact in twin gestation is less understood. Our objective was to estimate the influence of total maternal weight gain on preterm delivery in twin pregnancies.

Methods

We conducted a retrospective cohort study including diamniotic twin pregnancies with spontaneous labor delivered at 28 + 0 weeks or later. We analyzed the influence of total weight gain according to Institute of Medicine (IOM) cut-offs on the development of preterm delivery (both less than 34 and 37 weeks). Outcome were compared between under and normal weight gain and between over and normal weight gain separately using Fisher’s exact test with Holm-Bonferroni correction.

Results

One hundred seventy five women were included in the study and divided into three groups: under (52.0%), normal (41.7%) and overweight gain (6.3%). Normal weight gain was associated with a reduction in the rate of preterm delivery compared to under and over weight gain [less than 34 weeks: under vs. normal OR 4.97 (1.76–14.02), over vs. normal OR 4.53 (0.89–23.08); less than 37 weeks: OR 3.16 (1.66–6.04) and 6.51 (1.30–32.49), respectively].

Conclusions

Normal weight gain reduces spontaneous preterm delivery compared to over and underweight gain.

Maternal weight gain and associations with longitudinal fetal growth in dichorionic twin pregnancies: a prospective cohort study

Background: Maternal metabolic demands are much greater with twin gestations; however, there are no accepted recommendations for maternal weight gain in twin pregnancies.Objective: We assessed the association of maternal weight gain and fetal growth in dichorionic twins throughout pregnancy.Design: This was a prospective US cohort study (n = 143, 2012-2013) of dichorionic twin pregnancies with known birth outcomes followed from enrollment (11-13 wk) and for ≤6 research visits throughout gestation. Maternal prepregnancy weight was self-reported, and current weight was measured at each research visit and abstracted from prenatal records. Fetal biometry was assessed by ultrasound at each research visit. Maternal weight and twin-pair fetal size trajectories across gestation were modeled. The adjusted associations between maternal weight gain from 0 to 13, 14 to 20, 21 to 27, and 28 to 34 wk and fetal growth at the subsequent week (i.e., 14, 21, 28, and 35 wk, respectively) were estimated with the use of linear regression.Results: The mean ± SD maternal weight gain from 0 to 13, 14 to 20, 21 to 27, and 28 to 34 wk was 2.8 ± 3.0 kg, 3.9 ± 1.2 kg, 3.8 ± 1.4 kg, and 4.4 ± 2.2 kg, respectively, with a total gain of 17.7 ± 7.4 kg. Maternal weight gain from 0 to 13 wk (first trimester) was not associated with fetal size at 14 wk. Maternal weight gain from 14 to 20 and 21 to 27 wk (second trimester) was significantly associated with increased fetal weight at 21 wk [increase of 10.5 g/kg maternal weight gain (95% CI: 1.2, 19.8 g)] and 28 wk [increase of 21.3 g/kg maternal weight gain (95% CI: 0.6, 42.0 g)]. Maternal weight gain from 14 to 20 wk was associated with increased twin abdominal circumference (AC) and biparietal diameter at 21 wk. Maternal weight gain from 21 to 27 wk was associated with increased femur and humerus lengths at 28 wk.Conclusion: Maternal weight gain was associated with dichorionic twin fetal growth in the second trimester only, driven by an association with AC earlier in second trimester and long bones later in the second trimester.

Nutrition Recommendations in Pregnancy and Lactation

The nutritional status of a woman during pregnancy and lactation is not only critical for her health but for future generations. Although a nutritionist or registered dietitian can help facilitate dietary counseling and interventions, physicians also need to be cognizant of nutritional needs during pregnancy because they differ significantly compared with nonpregnant populations. Furthermore, an individualized approach to nutritional counseling that considers a woman's nutritional status and body mass index is recommended.

Nutrition for Multiples

In 2012 there were 135,943 infants of multiple pregnancies born in the United States, nearly a 2-fold increase since 1980, with twins accounting for 96% of all multiple births. To date, most perinatal morbidities associated with multiple births have proven resistant to technological or pharmaceutical interventions. Maternal nutrition can have a profound effect on the course and outcome of multiple pregnancy, with the goal of achieving optimal intrauterine growth and birthweights, and minimizing prenatal and perinatal complications for the mother and her children.

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

Our objective was to systematically review the data interrogating the association between gestational weight gain (GWG) and maternal and child health among women with twin gestations. We identified 15 articles of twin gestations that studied GWG in relation to a maternal, perinatal or child health outcome and controlled for gestational age at delivery and prepregnancy body mass index. A positive association between GWG and fetal size was consistently found. Evidence on preterm birth and pregnancy complications was inconsistent. The existing studies suffer from serious methodological weaknesses, including not properly accounting for the strong correlation between gestational duration and GWG and not controlling for chorionicity. In addition, serious perinatal outcomes were not studied, and no research is available on the association between GWG and outcomes beyond birth. Our systematic review underscores that GWG in twin gestations is a neglected area of research. Rigorous studies are needed to inform future evidence-based guidelines.

The association between maternal weight gain and spontaneous preterm birth in twin pregnancies

OBJECTIVE

To estimate the association between maternal weight gain and SPTB in twin pregnancies.

METHODS

A case-control study of patients with twin pregnancies and a normal prepregnancy BMI (18.5-24.9 kg/m(2)) in one maternal-fetal medicine practice from 2005 to 2013. We reviewed maternal weight in six time periods: prepregnancy, 12-15 6/7 weeks, 16-19 6/7 weeks, 20-23 6/7 weeks, 24-27 6/7 weeks and 28-31 6/7 weeks. We compared maternal weight gain patterns across pregnancy between patients who did and did not have SPTB <32 weeks. Student's t-test and chi-square were used for analysis.

RESULTS

In total, 382 patients were included, 29 (7.6%) of whom had SPTB <32 weeks. The baseline height, weight and BMI did not differ between the groups, nor did maternal age, IVF status, race or chorionicity. Patients with SPTB <32 weeks had significantly less weight gain as early as 15 6/7 weeks (2.9 ± 4.6 versus 7.3 ± 6.6 lb, p < 0.001), and this continued until 31 6/7 weeks (25.3 ± 8.7 versus 30.8 ± 10.9 lb, p = 0.037).

CONCLUSIONS

In twin pregnancies with a normal prepregnancy BMI, there is a significant association between SPTB <32 weeks and lower maternal weight gain, particularly prior to 16 weeks. Future studies are needed to test if prepregnancy or early nutritional interventions in twin pregnancies can reduce the risk of preterm birth and improve neonatal outcomes in this high-risk population.

Midupper Arm Circumference (MUAC) Changes in Late Pregnancy Predict Fetal Growth in Twins

The objective of the study was to test the hypothesis that changes in arm anthropometry can be used to determine the risk of faltering growth in twin gestations. Serial data on midupper arm circumference (MUAC) and maternal weight gain were collected from a sample of 156 mothers. Changes in MUAC were monitored from 20 to 34 weeks. Women with a large loss of MUAC (greater than 1.5 cm), particularly when it occurred within two to four weeks of delivery, were significantly heavier, had higher pregravid Body Mass Indexes (BMIs), but gained less weight than mothers with no change in MUAC. In analysis of covariance models adjusting for length of gestation, black ethnicity, males per twin pair, monochorionicity, and baseline MUAC at 20 weeks, a large loss of MUAC was associated with significantly lower birthweight (2263 g vs. 2499 g) and birthweight z-score (–0.92 SDU vs. –0.39 SDU). Changes in MUAC from 20 to 34 weeks, and especially near delivery, are significantly associated with fetal growth in twin pregnancies. A positive change may indicate that the mother has adequate dietary intake or nutrient stores to continue to accrue lean body mass and support fetal growth, while a loss of MUAC indicates that dietary intake or nutrient stores may be inadequate. This simple, relatively precise, measure of change in maternal body composition during pregnancy may be useful in identifying twin pregnancies at risk for faltering intrauterine growth, particularly among overweight or obese women.

The Hispanic Paradox in Twin Pregnancies

The objective of this study was to compare length of gestation, fetal growth, and birthweight by race/ethnicity and pregravid weight groups in twin pregnancies. Three thousand and thirty-six twin pregnancies of 28 weeks or more gestation were divided by race/ethnicity (White, Black and Hispanic), and pregravid body mass index (BMI) groups (less than 25.0 vs. 25.0 or more). Outcomes were modeled using multiple regression, controlling for confounders, with White non-Hispanic women as the reference group. Hispanic women had the highest average birthweight and the longest gestation, as well as the lowest proportions of low birthweight, very low birthweight, preterm and early preterm births of the 3 race/ethnicity groups. In the multivariate analyses, Hispanic women had significantly longer gestations (by 7.8 days) and faster rates of fetal growth midgestation (20 to 28 weeks, by 17.4 g/week) and late gestation (after 28 weeks, by 5.3 g/week), whereas Black women had significantly slower rates of fetal growth (by 5.7 g/week and by 4.5 g/week, respectively). These findings in twins reflect the racial and ethnic disparities previously shown in singletons, including the Hispanic paradox of longer gestations and higher rates of fetal growth.

Implementation of the new institute of medicine gestational weight gain guidelines

In May 2009, the Institute of Medicine (IOM) introduced revised gestational weight gain guidelines that were based on balancing the benefits and risks of weight gain for both the mother and child's health. This article provides an overview of these new recommendations, explaining the key changes made from the previous 1990 IOM recommendations. The important role of health care providers of pregnant women in the implementation of the new recommendations is detailed, and specific guidance for troubleshooting issues that may be encountered when helping women achieve appropriate gestational weight gains is provided.

Weight gain in twin pregnancies and adverse outcomes: examining the 2009 Institute of Medicine guidelines

OBJECTIVE

To estimate whether the weight gain recommendations for twin pregnancies in the 2009 Institute of Medicine (IOM) guidelines are associated with improved perinatal outcomes.

METHODS

A cohort of 297 twin pregnancies was identified from a single practice with measured prepregnancy body mass index (BMI) and weight gain during pregnancy. Recommended IOM guidelines were applied to our cohort based on prepregnancy BMI categories (normal weight, overweight, obese). Pregnancy outcomes were compared between patients whose weight gain met or exceeded the IOM recommendations and patients who did not meet these recommendations.

RESULTS

Patients with normal prepregnancy BMIs whose weight gain met the IOM recommendations had significantly improved outcomes compared with patients who did not meet the IOM recommendations. They were less likely to have preterm birth before 32 weeks (5.0% compared with 13.8%) and spontaneous preterm birth before 32 weeks (3.4% compared with 11.5%). They also delivered significantly larger neontates (larger twin birth weight 2,582.1+/-493.4 g compared with 2,370.3+/-586.0 g; smaller twin birth weight 2,277.0+/-512.1 g compared with 2,109.3+/-560.9 g) and were significantly more likely to have both neonates weigh more than 2,500 g (38.8% compared with 22.5%) and more than 1,000 g (97.5% compared with 91.2%) and were less likely to deliver any twin with a birth weight lower than the fifth percentile for gestational age (21.5% compared with 35.0%).

CONCLUSION

In women with twin pregnancies and normal starting BMIs, weight gain during pregnancy is significantly associated with improved outcomes, including a decreased risk of prematurity and larger birth weights.

LEVEL OF EVIDENCE

II.

Maternal obesity as a risk factor for very pre-term delivery in dichorionic twin pregnancies

We attempt here to identify the maternal characteristic factors most strongly associated with the increased risk of very pre-term delivery in dichorionic twin deliveries. Data were collected from 24 dichorionic twin pregnancies who were born at <32 weeks' gestation (very pre-term delivery) and 245 dichorionic twin pregnancies, who were born at 37-40 weeks' gestation as controls. Data included maternal age, height, body weight, body mass index (BMI), history of abortion, parity, maternal smoking, history of infertility therapy, such as in vitro fertilisation and/or embryo reduction, chronic hypertension and diabetes mellitus. Using logistic regression, the risk of very pre-term delivery was significantly increased among obese women (BMI >or=30 during prepregnancy; the adjusted odds ratio: 5.1, 95% confidence intervals: 1.2-21, p = 0.01). The current results indicate that maternal obesity is an independent risk factor for very pre-term delivery in dichorionic twin pregnancies.

Optimal nutrition for improved twin pregnancy outcome

Twin pregnancies contribute a disproportionate degree to perinatal morbidity, partly because of increased risks of low birth weight and prematurity. Although the cause of the morbidity is multifactorial, attention to twin-specific maternal nutrition may be beneficial in achieving optimal fetal growth and birth weight. Achievement of body mass index (BMI)-specific weight gain goals, micronutrient and macronutrient supplementation specific to the physiology of twin gestations, and carbohydrate-controlled diets are recommended for optimal twin growth and pregnancy outcomes. The daily recommended caloric intake for normal-BMI women with twins is 40-45 kcal/kg each day, and iron, folate, calcium, magnesium, and zinc supplementation is recommended beyond a usual prenatal vitamin. Daily supplementation of docosahexaenoic acid and vitamin D should also be considered. Multiple gestation-specific prenatal care settings with a focus on nutritional interventions improve birth weight and length of gestation and should be considered for the care of women carrying multiples. Antepartum lactation consultation can also improve the rate of postpartum breastfeeding in twin pregnancies. Twin gestation-specific nutritional interventions seem effective in improving the outcome of these pregnancies and should be emphasized in the antepartum care of multiple gestations. This review examines the available evidence and offers recommendations for twin pregnancy-specific nutritional interventions.

Maternal morbidity and infant death in twin vs triplet and quadruplet pregnancies

OBJECTIVE

The purpose of this study was to calculate nationally representative, population-based estimates of maternal and neonatal risks in triplet and quadruplet pregnancies compared with twin pregnancies.

STUDY DESIGN

The study population included 316,696 twin, 12,193 triplet, and 778 quadruplet pregnancies from the 1995-2000 Matched Multiple Birth Data Set. Adjusted odds ratios (AORs) and 95% CIs estimated the risk of complications and were controlled for maternal age, race, parity, and smoking status.

RESULTS

Compared with mothers of twins, mothers of triplets and quadruplets were more likely to be diagnosed with preterm premature rupture of membranes (AORs, 1.53, 1.74, respectively), pregnancy-associated hypertension (AORs, 1.22, 1.27), and excessive bleeding (AORs, 1.50, 2.22), to require tocolysis (AORs, 2.85, 5.03), and to be delivered by cesarean (AORs, 6.55, 7.38) at < 29 weeks of gestation (AORs, 3.76, 7.96), and to have > or = 1 infants die (AORs, 3.02, 4.07).

CONCLUSION

Triplet and quadruplet pregnancies have significantly higher risks than twin pregnancies for most maternal and neonatal complications. Maternal anthropometric, nutritional, and previous reproductive factors may be particularly important in the reduction of these excess risks and improvement of outcomes in multiple births.

Twin weight discordance and maternal weight gain in twin pregnancies

OBJECTIVE

To evaluate the association between twin weight discordance and maternal weight change during the gestational period.

METHOD

One hundred forty-seven twin pregnancies (Group A: <25%, Group B: > or =25% birth weight discordance) were analyzed using Student's t-test, chi(2)-test, and two-way ANOVA at three gestational intervals: before 18 weeks, 18 to 28 weeks, and 28 weeks to birth.

RESULT

There was no statistically significant difference between the two groups involving maternal age, parity, duration of pregnancy, height, pregravid weight, and conception method. Group A showed a pattern of constantly increasing maternal weight without a significant change in the twin weight discordance throughout gestation. However, Group B showed a fluctuation in maternal BMI with remarkably elevated twin weight discordance at 28 weeks to birth.

CONCLUSION

The results suggest that in twin pregnancies constant maternal weight gain throughout gestation is important for maintaining a twin weight discordance of less than 25%.

Size and morbidity in Malawian twins

OBJECTIVE

Twins in developing countries may be disadvantaged due to their small size at birth, compromised nutrition and high infection risk. Although twinning is common in Africa, there are few longitudinal studies of growth and morbidity in this high-risk group. The aim of the present paper was to describe growth and morbidity of Malawian twins compared to singletons.

METHODS

Morbidity episodes were recorded at 4 weekly intervals and at extra visits made to health centres for illness. Weight, length, head and arm circumference were recorded at birth and weight, length and MUAC at 4 weekly intervals to 52 weeks of age.

RESULTS

Twins showed reduced fetal growth compared to singletons, with increasing fall-off in percentiles from 33 weeks gestation. Infant growth percentiles for twins were below those for singletons at all ages, but showed no fall-off from singleton percentile values. There were no differences in morbidity incidence during infancy between twins and singletons.

CONCLUSION

Malawian twins showed no catch-up growth during infancy, their smaller size was not associated with higher morbidity incidence compared to singletons.

Nutrition and multiple gestation

Multiple pregnancy represents a state of magnified nutritional requirements, resulting in a greater nutrient drain on maternal resources and an accelerated depletion of nutritional reserves. The accelerated starvation which occurs in pregnancy is exaggerated with a multiple gestation, particularly during the second half of pregnancy, with more rapid depletion of glycogen stores and resultant metabolism of fat between meals and during an overnight fast. A reduced glucose stream from mother to fetus results in slower fetal growth, smaller birth size, as well as a higher risk of preterm labor and preterm birth. For this reason, diet therapy with a diabetic regimen of 20% of calories from protein, 40% of calories from carbohydrate, and 40% of calories from fat may be particularly useful. Iron-deficiency anemia has also been linked to preterm delivery and other adverse pregnancy outcomes. Mobilization of maternal iron stores, in addition to an adequate amount and pattern of gestational weight gain (including BMI-specific weight gain goals by 20 and 28 weeks gestation), has been associated with significantly better fetal growth and longer gestations in twin pregnancies. Supplementation with calcium, magnesium, and zinc, as well as multivitamins and essential fatty acids may also reduce pregnancy complications and improve postnatal health for infants born from a multiple gestation. Diet therapy for women pregnant with multiples is an important component of effective prenatal care.

Fetal growth rates and the very preterm delivery of twins

OBJECTIVE

Our objective was to determine whether slow fetal growth rates and twin growth patterns from 20 weeks' gestation to delivery are associated with very preterm delivery.

STUDY DESIGN

Available charts were reviewed for twin pregnancies, delivered between 1979 and 2002, at 4 U.S. medical centers. The sample of 1612 pregnancies delivered at 28 week's gestation or greater and had at least 2 ultrasound evaluations of fetal size from 20 to 28 weeks or from 28 weeks to delivery for estimation of fetal growth rates (grams per week). Slow fetal growth (below the 10th percentile) was defined as less than 90 grams per week at 20-28 weeks and 168 g/week from 28 weeks to delivery. The main outcome measure was the timing of delivery.

RESULTS

Of the women delivering twins, 5.3% delivered extremely preterm (28-30 weeks), 8.5% very preterm (31-32 weeks), and 40.1% preterm (33-36 weeks). Patterns of growth for the pair were highly associated with very preterm delivery. Compared with neither growing slowly (1.7%), 4.9% delivered very preterm if only 1 twin grew slowly. Very preterm was 14.6% (adjusted odds ratio 9.81; 95% confidence interval, 3.50-27.48) with both growing slowly from 28 weeks on and 20.0% (adjusted odds ratio 15.04; 95% confidence interval 5.13-44.11) with both growing slowly over both intervals. Survival analyses indicated that twins with normal growth in both intervals remained undelivered for a significantly longer number of days (P < .0001) than pairs in which one or both twins were growing slowly.

CONCLUSION

Very preterm delivery of twins seems to be preceded by slowed or compromised fetal growth for the pair.

Nutrition in multiple gestations

Multiple pregnancies represent a state of magnified nutritional requirements, resulting in a greater nutrient drain on maternal resources and an accelerated depletion of nutritional reserves. Maternal weight gain to 20 weeks and between 20 and 28 weeks has the greatest effect on birthweight in twin and triplet pregnancies, particularly among underweight women. Parity, which most likely represents a higher proportion of body fat, has a positive effect on pregnancy outcome, with an average 7 to 10 days longer gestation for multiparous versus nulliparous women. In addition to being the nutrients most often lacking in a woman's diet, calcium, magnesium, and zinc have been identified as having the most potential for reducing pregnancy complications and improving outcomes.

The cost of twin pregnancy: maternal and neonatal factors

OBJECTIVE

The purpose of this study was to evaluate factors affecting birth charges in twin pregnancies.

STUDY DESIGN

Clinical and financial data were obtained on 1486 twin pregnancies delivered between 1995 to 2002 at medical centers in Maryland, Florida, Michigan, and South Carolina. Maternal and neonatal length of stay (LOS) and charges were modeled by gestational age and other risk factors using a general linear model.

RESULTS

Maternal and infant birth admission LOS and charges increased significantly with a decline in gestational age. Maternal LOS and charges were also significantly increased by cesarean delivery and preeclampsia. Newborn LOS and charges increased significantly by monochorionicity and slowed growth between 20 to 28 weeks. For mother and infants, the shortest LOS and lowest birth charges were at 37 to 38 weeks.

CONCLUSION

These findings reflect the substantial maternal and neonatal morbidity associated with twin pregnancies, and demonstrate that 37 to 38 weeks is their optimal gestation.

Fetal phenotypes and neonatal and early childhood outcomes in twins

OBJECTIVES

The purpose of this study was to evaluate factors associated with, and postnatal consequences of, altered patterns of fetal growth in twins.

STUDY DESIGN

Fetal growth was measured at 28 weeks' gestation on 218 twins, including head circumference, abdominal circumference, and femur length, and characterized as > or < or =10th %ile; children were followed up until the age of three years. Logistic regression was used to generate odds ratios of perinatal factors associated with reduced fetal growth.

RESULTS

Maternal height <62 inches was associated with reductions in femur length (adjusted odds ratio [AOR] 3.88, 95% CI 1.42-10.57) and abdominal circumference (AOR 8.63, 95% CI 2.41-30.94), while primiparity had a protective effect on both of these fetal measurements (AOR 0.28, 95% CI 0.13-0.64, and AOR 0.18, 95% CI 0.06-0.60, respectively), as well as head circumference (AOR 0.32, 95% CI 0.15-0.69). Smoking adversely affected femur and head growth (AOR 24.10, 95% CI 3.69-157.57, and AOR 10.82, 95% CI 1.73-67.79, respectively). Fetal reduction adversely affected femur and abdomen growth (AOR 5.85, 95% CI 1.52-22.51 and AOR 4.90, 95% CI 1.01-23.86, respectively), and monochorionicity and maternal weight gain <0.65 lb/wk before 20 weeks adversely affected femur growth (AOR 5.47, 95% CI 1.65-18.10, and AOR 3.39, 95% CI 1.34-8.59, respectively). At age 3 years, all categories of twins with reduced growth by 28 weeks' gestation were significantly shorter in height, and those with reduced abdominal circumference or head circumference at 28 weeks were also significantly lighter in weight compared with twins with adequate fetal growth by 28 weeks' gestation.

CONCLUSION

These data identify short maternal height, smoking, monochorionicity, fetal reduction, and inadequate weight gain before 20 weeks as risk factors associated with reduced twin fetal growth by 28 weeks' gestation and significant residual reductions in height and weight through 3 years of age.

Risk factors for adverse outcomes in spontaneous versus assisted conception twin pregnancies

OBJECTIVE

To evaluate risk factors for adverse outcomes in spontaneous vs. assisted conception twin pregnancies.

DESIGN

Historical cohort study.

SETTING

Four academic tertiary medical centers.

PATIENT(S)

Women with twin pregnancies, including 2,143 spontaneous and 424 assisted conception; 2,492 nonreduced and 75 reduced.

INTERVENTION(S)

None (observational).

MAIN OUTCOME MEASURE(S)

Preeclampsia, preterm premature rupture of membranes, birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth (<10th percentile between 20 and 28 weeks).

RESULT(S)

Among nonreduced pregnancies, assisted conception was not significantly associated with any adverse outcomes; among nulliparas, the risk for preeclampsia was increased regardless of method of conception; among spontaneous conceptions, the risks for preterm premature rupture of membranes, low birth weight, very low birth weight, and slowed midgestation fetal growth were increased. Among all pregnancies, fetal reduction increased risks for birth <32 weeks and <30 weeks, low birth weight, very low birth weight, and slowed midgestation fetal growth. Among nulliparas with assisted conceptions, fetal reduction increased the risks for birth <30 weeks, very low birth weight, and slowed midgestation fetal growth.

CONCLUSION(S)

These findings indicate that in twin pregnancies, assisted conception is not a risk factor for adverse outcomes, but rather specific factors that are more common among these pregnancies, such as nulliparity and fetal reduction, increase risks.

Specialized prenatal care and maternal and infant outcomes in twin pregnancy

OBJECTIVE

This study was undertaken to evaluate the effect of a prenatal nutrition and education program on twin pregnancy, neonatal, and early childhood outcomes.

STUDY DESIGN

This prospective intervention study of women who participated in a specialized program (Program Pregnancies) versus nonparticipants included twice-monthly visits, dietary prescription of 3000 to 4000 kcal per day, multimineral supplementation, and patient education.

RESULTS

Program Pregnancies were associated with improved pregnancy outcomes (preeclampsia, adjusted odds ratio [AOR] 0.41, 95% CI, 0.23-0.75; preterm premature rupture of membranes, AOR 0.35, 95% CI, 0.20-0.60; delivery <36 weeks, AOR 0.62, 95% CI, 0.43-0.89; low birth weight, AOR 0.42, 95% CI, 0.29-0.61), significantly longer gestations (+7.6 days), higher birth weights (+220 g), lower neonatal morbidity (retinopathy of prematurity, necrotizing enterocolitis, intraventricular hemorrhage, or ventilator support, AOR 0.44, 95% CI, 0.31-0.62), length of stay (-5.3 days), and cost per twin (-14,023 dollars). Through 3 years of age, program children were significantly less likely to be rehospitalized (AOR 0.31, 95% CI, 0.11-0.91) or to be developmentally delayed (AOR 0.65, 95% CI, 0.44-0.96).

CONCLUSION

Program participation was associated with improved outcomes at birth and through age 3 years.

Antenatal factors associated with significant birth weight discordancy in twin gestations

OBJECTIVE

The purpose of this study was to evaluate factors that are associated with significant birth weight discordancy.

STUDY DESIGN

As a part of an ongoing collaborative study of twins, maternal and fetal data were obtained from the medical records of twin gestations at eight medical centers. The study population was divided into groups by difference in birth weight discordancy (>or=20%, >or=25%, and >or=30%)

RESULTS

Severe birth weight discordancy was associated with fetal growth deceleration by 20 to 28 weeks (adjusted odds ratio, 4.90; 95% CI, 3.15-7.64) and between 28 weeks to birth (adjusted odds ratio, 3.48; 95% CI, 1.72-7.06). Antenatal bleeding (adjusted odds ratio, 1.86; 95% CI, 1.08-3.21), preeclampsia (adjusted odds ratio, 1.70, 95% CI, 1.21-2.41), and monochorionicity (adjusted odds ratio, 2.35, 95% CI, 11.71-3.23) were also associated with birth weight discordancy.

CONCLUSION

These data demonstrate the importance of the early diagnosis of placental chorionicity, because monochorionicity is associated with a 2-fold increase in birth weight discordancy in twin gestations.

The association between maternal factors and perinatal outcomes in triplet pregnancies

OBJECTIVE

The purpose of this study was to evaluate the associations between maternal factors and outcomes in triplet pregnancies.

STUDY DESIGN

This was a historic cohort study of 194 triplet pregnancies of >or=24 weeks of gestation that were delivered from 1983 through 2001 from five medical centers.

RESULTS

In analyses that were limited to pregnancies with all live-born triplets (178 pregnancies), women with a previous good outcome (>2500 g + >37 weeks of gestation) had longer gestations (+7.9 days, P =.03), better rates of fetal growth (+4.9 g/wk, P <.0001), and higher birth weights (+153 g, P <.0001). Maternal weight gains of <36 pounds by 24 weeks of gestation were associated with lower birth weights (-197 g, P <.0001), and fetal growth rates at <or=25th percentile were associated with a shorter length of gestation (-36.7 days, P <.0001).

CONCLUSION

Previous obstetric outcome and weight gain by 24 weeks of gestation were associated significantly with fetal growth rate and birth weight; fetal growth rate, in turn, was associated significantly with length of gestation.

Intrauterine growth retardation and long-term effects on growth

The authors present intrauterine growth retardation (IUGR) as an entity with significant prevalence, morbidity, and mortality. They discuss short-term and long-term sequelae, and particularly emphasize long-term growth disabilities. The authors review the most important trials with human growth hormone that have been carried out recently to maximize the growth and final height potential of children affected with IUGR. They also highlight the most recent advances in the field of fetal growth, with special attention to genetic and endocrine factors. Finally, the authors discuss in detail epidemiological and clinical evidence of the causes of IUGR in relation to several adult onset disorders.

The importance of early weight gain in the intrauterine growth and birth weight of twins

OBJECTIVE

It was our objective to evaluate the association between early maternal weight gain (before 20 weeks), midpregnancy weight gain (20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins.

STUDY DESIGN

This historic cohort study was based on 1564 births of live twins >/=28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Charleston, South Carolina, and Ann Arbor, Michigan.

RESULTS

Early fetal growth was affected only by smoking and chorionicity. Factors in models of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal weight gain, smoking, and pre-eclampsia. Increased midpregnancy fetal growth was associated with early maternal weight gain (10.91 g/wk per pound per week) and midpregnancy maternal weight gain (15.89 g/wk per pound per week). Increased late fetal growth was associated with early maternal weight gain (16.86 g/wk per pound per week) and midpregnancy maternal weight gain (23.88 g/wk per pound per week). Increased birth weight was associated with early (283.02 g per pound per week), mid (163.58 g per pound per week), and late (69.76 g per pound per week) maternal weight gains.

CONCLUSIONS

These findings confirm the importance of early maternal weight gain in twin fetal growth and birth weight.

Prenatal care and multiple pregnancy

Prenatal care of multiple pregnancy presents a variety of nursing challenges. Specialized care, beginning in early pregnancy, can have a significant impact on the outcome for mothers and neonates. Dramatically increasing roles for advanced technology in the care of multifetal pregnancies must be balanced with families' needs for education and support.

Maternal nutrition in twin gestations: weight gain, cravings and aversions, and sources of nutrition advice

BACKGROUND

Maternal nutrition has a strong influence on singleton and twin birthweight. This study evaluated the association between twin birthweight and maternal pregravid body mass index (BMI), weight gain, and cravings and aversions. Information was also obtained regarding sources of nutrition advice and advised versus actual weight gain.

METHODS

This study is based on data from interviews with 928 mothers of twins. Univariate analysis included comparisons by source of nutritional advice, birthweight categories, and categories of cravings and aversions. Multiple logistic regression was used to formulate models for mean twin birthweights > 1,500 g and > 2,500 g.

RESULTS

Mothers who received their nutrition advice from a registered dietitian had the highest weight gains and the lowest proportion of birthweights < 1,500 g. For mean twin birthweight > 2,500 g, the final model included prematurity, pregravid BMI, and weight gain; for birthweights > 1,500 g, the model additionally included maternal age and aversions.

CONCLUSIONS

Maternal pregravid BMI and gestational weight gain were shown to be important factors influencing twin birthweight. Nutrition advice, particularly from a registered dietitian, may be vital in assuring adequate weight gain, and therefore better birthweights, for these high-risk pregnancies.