Prenatal care: Second and third trimesters
- Charles J Lockwood, MD, MHCM
Charles J Lockwood, MD, MHCM
- Section Editor — Obstetrics
- Senior Vice President, USF Health
- Dean, Morsani College of Medicine
- Professor, Obstetrics and Gynecology
- University of South Florida
- Urania Magriples, MD
Urania Magriples, MD
- Associate Professor of Obstetrics and Gynecology
- Yale University School of Medicine
The goal of prenatal care is to ensure the birth of a healthy baby with minimal risk for the mother. Prenatal care is not a single intervention; instead, it represents a series of assessments and interventions over time that is variously applied by different practitioners. The "quality" of prenatal care and the effect of individual components on outcome are thus difficult to measure.
After the initial prenatal assessment and patient counseling, prenatal care is directed at ongoing evaluation of the health status of both mother and fetus, anticipation of problems, and intervention, if possible, to prevent or minimize morbidity. This topic will discuss prenatal care in the second and third trimesters. Prenatal issues related to the first visit and first trimester are reviewed separately. (See "Prenatal care: Initial assessment".)
FREQUENCY OF PRENATAL VISITS
Observational data suggest that prenatal care saves lives compared to no prenatal care  and show an association between the number of antenatal visits and/or early gestational age at the initiation of care and pregnancy outcomes, after controlling for confounding factors (eg, length of gestation) . However, there are limited data as to what constitutes the optimal number and frequency of prenatal visits, or the optimal content of those visits.
In the United States, the typical intervals for prenatal visits for nulliparous women with uncomplicated pregnancies are every 4 weeks until 28 weeks of gestation, every 2 weeks from 28 to 36 weeks, and then weekly until delivery . Parous women with uncomplicated medical and obstetrical histories can be seen less frequently. Women with problems are seen more frequently, depending on the nature of the problems. According to this schedule, an uncomplicated pregnancy where the first visit is at six weeks of gestation and the last visit is at 41 weeks will comprise 16 prenatal visits. While the above visit schedule is commonly followed, it requires significant effort and planning on the part of the patient without clear evidence of benefit.
●In a cohort study of over 7200 women with low-risk pregnancies, there were no differences in neonatal intensive care unit admissions, five-minute Apgar score <7, neonatal demise, or small for gestational age infants among women who had more than 10 prenatal visits and those who had 10 or fewer prenatal visits . While the women in the high utilization group were 33 percent more likely to undergo induction of labor and 50 percent more likely to have a cesarean delivery than the women in the low utilization group, there are insufficient data to conclude a causal relationship.
- Kaunitz AM, Spence C, Danielson TS, et al. Perinatal and maternal mortality in a religious group avoiding obstetric care. Am J Obstet Gynecol 1984; 150:826.
- Dowswell T, Carroli G, Duley L, et al. Alternative versus standard packages of antenatal care for low-risk pregnancy. Cochrane Database Syst Rev 2015; :CD000934.
- American College of Obstetricians and Gynecologists, American Academy of Pediatrics. Guidelines for Perinatal Care, 7th ed, 2012.
- Carter EB, Tuuli MG, Caughey AB, et al. Number of prenatal visits and pregnancy outcomes in low-risk women. J Perinatol 2016; 36:178.
- Klerman LV, Ramey SL, Goldenberg RL, et al. A randomized trial of augmented prenatal care for multiple-risk, Medicaid-eligible African American women. Am J Public Health 2001; 91:105.
- Villar J, Farnot U, Barros F, et al. A randomized trial of psychosocial support during high-risk pregnancies. The Latin American Network for Perinatal and Reproductive Research. N Engl J Med 1992; 327:1266.
- National Institute for Health and Clinical Excellence. Antenatal care: Routine care for the healthy pregnant woman. www.nice.org.uk (Accessed on April 19, 2012).
- WHO recommendations on antenatal care for a positive pregnancy experience. World Health Organization, Geneva, 2016. http://www.who.int/reproductivehealth/publications/maternal_perinatal_health/anc-positive-pregnancy-experience/en/ (Accessed on December 01, 2016).
- Committee on Obstetric Practice. The American College of Obstetricians and Gynecologists Committee Opinion no. 630. Screening for perinatal depression. Obstet Gynecol 2015; 125:1268.
- Siu AL, US Preventive Services Task Force (USPSTF), Bibbins-Domingo K, et al. Screening for Depression in Adults: US Preventive Services Task Force Recommendation Statement. JAMA 2016; 315:380.
- Macdonald-Wallis C, Silverwood RJ, Fraser A, et al. Gestational-age-specific reference ranges for blood pressure in pregnancy: findings from a prospective cohort. J Hypertens 2015; 33:96.
- Cnossen JS, Vollebregt KC, de Vrieze N, et al. Accuracy of mean arterial pressure and blood pressure measurements in predicting pre-eclampsia: systematic review and meta-analysis. BMJ 2008; 336:1117.
- Gribble RK, Meier PR, Berg RL. The value of urine screening for glucose at each prenatal visit. Obstet Gynecol 1995; 86:405.
- Watson WJ. Screening for glycosuria during pregnancy. South Med J 1990; 83:156.
- Carroli G, Rooney C, Villar J. How effective is antenatal care in preventing maternal mortality and serious morbidity? An overview of the evidence. Paediatr Perinat Epidemiol 2001; 15 Suppl 1:1.
- Rhode MA, Shapiro H, Jones OW 3rd. Indicated vs. routine prenatal urine chemical reagent strip testing. J Reprod Med 2007; 52:214.
- Gardosi J, Francis A. Controlled trial of fundal height measurement plotted on customised antenatal growth charts. Br J Obstet Gynaecol 1999; 106:309.
- Sibai BM, Abdella TN, Spinnato JA, Anderson GD. Eclampsia. V. The incidence of nonpreventable eclampsia. Am J Obstet Gynecol 1986; 154:581.
- Leung WC, Pun TC, Wong WM. Undiagnosed breech revisited. Br J Obstet Gynaecol 1999; 106:638.
- Society for Maternal-Fetal Medicine Publications Committee, with assistance of Vincenzo Berghella. Progesterone and preterm birth prevention: translating clinical trials data into clinical practice. Am J Obstet Gynecol 2012; 206:376.
- Romero R, Nicolaides K, Conde-Agudelo A, et al. Vaginal progesterone in women with an asymptomatic sonographic short cervix in the midtrimester decreases preterm delivery and neonatal morbidity: a systematic review and metaanalysis of individual patient data. Am J Obstet Gynecol 2012; 206:124.e1.
- Centers for Disease Control (CDC). CDC criteria for anemia in children and childbearing-aged women. MMWR Morb Mortal Wkly Rep 1989; 38:400.
- Institute of Medicine. Iron deficiency anemia: recommended guidelines for the prevention, detection, and management among US children and women of childbearing age. 1993, Washington, DC.
- World Health Organization. Iron Deficiency Anaemia. Assessment, Prevention, and Control. A guide for programme managers. 2001. http://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf (Accessed on September 06, 2011).
- Workowski KA, Bolan GA, Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep 2015; 64:1.
- Blatt AJ, Lieberman JM, Hoover DR, Kaufman HW. Chlamydial and gonococcal testing during pregnancy in the United States. Am J Obstet Gynecol 2012; 207:55.e1.
- American College of Obstetrics and Gynecology Committee on Obstetric Practice. ACOG Committee Opinion No. 418: Prenatal and perinatal human immunodeficiency virus testing: expanded recommendations. Obstet Gynecol 2008; 112:739.
- FREQUENCY OF PRENATAL VISITS
- Higher risk pregnancies
- SIGNS AND SYMPTOMS THAT SHOULD BE REPORTED TO THE HEALTH CARE PROVIDER
- FOLLOW-UP VISITS
- Ongoing assessments
- Periodic assessments
- - First trimester
- - 15 to 24 weeks of gestation
- Neural tube defects
- Trisomy 21
- Fetal anomalies
- Cervical length
- - 24 to 28 weeks of gestation
- Gestational diabetes
- RBC antibodies
- Hemoglobin or hematocrit
- - 28 to 36 weeks of gestation
- Sexually transmitted disease
- Group B beta-hemolytic streptococcus testing
- Estimated fetal weight
- Fetal assessment
- External cephalic version
- - 36 to 41 weeks of gestation
- Patient education in preparation for labor and delivery
- Patient education regarding postpartum issues
- MANAGEMENT OF PREGNANCY COMPLICATIONS
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS