At 28 weeks, more than 90% of babies can survive outside of the uterus if provided with high-quality medical care.The third trimester is from 29 weeks through 40 weeks.The number of pregnancies in women ages 15 to 44 is 133 per 1,000 women.In 2013, complications of pregnancy resulted in 293,000 deaths, down from 377,000 deaths in 1990.Important aspects of the menstrual history must be obtained.The woman should describe her usual menstrual pattern, including date of onset of last menses, duration, flow, and frequency.Preventing preterm birth and neonatal mortality: exploring the epidemiology, causes, and interventions. 2010;34(6):408-415Pub Med Article Mc Donald SD, Han Z, Mulla S, Beyene J. Overweight and obesity in mothers and risk of preterm birth and low birth weight infants: systematic review and meta-analyses. 2010;341:c3428Pub Med Article Nohr EA, Bech BH, Vaeth M, Rasmussen KM, Henriksen TB, Olsen J.
Additionally, as many as 25% of women bleed during their first trimester, further complicating the assessment.
Maternal Body Mass Index (BMI) in Early Pregnancy and Risks of Preterm Deliveries: All Deliveries From 1996 Through 2010 and Deliveries of Women With Information of BMI Recorded in the First Trimestere Table 4.
Maternal Body Mass Index (BMI) in Early Pregnancy (per unit BMI) and Risks of Preterm Deliveries: Analyses Are Stratified by Height, and Underweight Women (BMI Simmons LE, Rubens CE, Darmstadt GL, Gravett MG.
2013;309(22): doi:10.1001/jama.2013.6295.e Table 1. Associations Between Maternal Body Mass Index in Early Pregnancy and Other Maternal Characteristicse Table 2.
Maternal Body Mass Index (BMI) in Early Pregnancy and Risks of Extremely, Very, and Moderately Preterm Delivery: Women With Information of Gestational Age Estimated Both by Ultrasound and the Last Menstrual Period (LMP)e Table 3.