Antenatal Examinations

See also: Antenatal Care, Antenatal Screening for Down's Syndrome, Prenatal Diagnosis.
This article cannot cover all areas of clinical practice associated with the proper care of pregnant women, but gives an overview of important areas based on the latest guidance. For the full advice offered by NICE on routine care of healthy pregnant women, see the first reference at the end of the article.¹

• Diagnosis of pregnancy is best confirmed using a urine-testing kit that determines the presence of beta-hCG.
• Many women nowadays will have confirmed their own pregnancy by such means.
• Where the absence of menses is the only current indicator of early pregnancy, it is important to confirm pregnancy using a testing kit.
• An early ultrasound scan should be offered at 10–13 weeks, to determine gestational age and detect multiple pregnancies. This has added benefits of ensuring consistency of gestational age assessments and improving the performance of mid-trimester serum screening for Down's syndrome and reducing the need for induction of labour at >41 weeks.
• Crown-rump length is the best surrogate measure of gestational age.
• Pregnant women who present at or beyond 14 weeks' gestation should be offered an ultrasound scan to estimate gestational age using head circumference or biparietal diameter.

• Nulliparous patients with uncomplicated pregnancies should be seen over a schedule of ten appointments.
• Parous women with uncomplicated pregnancies should be seen over a schedule of seven appointments.

NICE recommend that the first antenatal appointment takes place early in pregnancy (before 12 weeks) and that it may need to be booked as a double appointment due to the large amount of information and assessments that need to be gone into.¹ The checklist below covers those areas that are considered important by NICE:

• Give mother information on her antenatal care and an opportunity to ask any questions/raise any concerns. Consider topics such as:
  • Diet:
    • All women should be informed at the booking appointment about the importance for their own and their baby’s health of maintaining adequate vitamin D stores during pregnancy and whilst breastfeeding.
    • 10 micrograms of vitamin D per day should be taken by women at risk. These include:
      • Women of South Asian, African, Caribbean or Middle Eastern family origin.
      • Women who have limited exposure to sunlight, such as women who are predominantly housebound, or usually remain covered when outdoors.
      • Women who eat a diet particularly low in vitamin D, such as women who consume no oily fish, eggs, meat, vitamin D-fortified margarine or breakfast cereal.
      • Women with a pre-pregnancy body mass index above 30 kg/m².
  • Lifestyle:
    • Advice on avoiding food-borne infections such as Listeriosis/Salmonella.
    • Benefits of gentle exercise and high-impact sports that should be avoided.
    • Safety of sexual intercourse.
    • Alcohol, smoking and other recreational drug use during pregnancy.
  • Available pregnancy care services.
  • Maternity and associated benefits.
  • Working and finishing work when pregnant.
  • Availability, purpose and logistics of screening tests in pregnancy.
• Identify women who may need special care (see list below in criteria for more specialised care section); plan pattern of care for pregnancy depending on parity/previous complications of pregnancy.
• Check blood group and RhD status.
• Offer blood test to screen for:
  • Anaemia.
  • Red-cell alloantibodies.
  • Hepatitis B virus.
  • HIV.
  • Rubella immunity status.
  • Syphilis serology.
  • Screening for sickle cell diseases and thalassaemias should be offered to all women as early as possible in pregnancy (ideally by 10 weeks). The type of screening depends upon the prevalence and can be carried out in either primary or secondary care.^2,3,4
• Urine testing to screen for asymptomatic bacteriuria
• The ‘combined test’ (nuchal translucency, beta-human chorionic gonadotrophin, pregnancy-associated plasma protein-A) should be offered to screen for Down’s syndrome between 11 weeks 0 days and 13 weeks 6 days. For women who book later in pregnancy the most clinically and cost-effective serum screening test (triple or quadruple test) should be offered between 15 weeks 0 days and 20 weeks 0 days.
• Offer early ultrasound scan to assess gestational age.
• Screening for gestational diabetes using risk factors is recommended
  in a healthy population. Women with any one of these risk factors should be offered testing for gestational diabetes at the booking appointment:
  • Body mass index above 30 kg/m².
  • Previous macrosomic baby weighing 4.5 kg or above.
  • Previous gestational diabetes.
  • Family history of diabetes (first-degree relative with diabetes).
  • Family origin with a high prevalence of diabetes:
    • South Asian (specifically women whose country of family origin is India, Pakistan or Bangladesh)
    • Black Caribbean
    • Middle Eastern (specifically women whose country of family origin is Saudi Arabia, United Arab Emirates, Iraq, Jordan, Syria, Oman, Qatar, Kuwait, Lebanon or Egypt)
• Offer 20 week ultrasound screening for fetal anomaly.
• Measure BMI.
• Check and record BP.
• Test urine for glycosuria/proteinuria.

For a full schedule of assessments at each of the antenatal assessments and what areas they should cover, see the first reference below (NICE guidance)¹ or the article on Antenatal Care.

Routine antenatal pelvic examination does not accurately assess gestational age, nor does it accurately predict preterm birth or cephalopelvic disproportion, so it is not recommended.

Routine breast examination is not recommended.

Patient should be weighed and her height measured so that her body mass index can be calculated as:

• BMI = Weight in Kilograms / (Height in Metres)².
• This can be used as a baseline for future weighing where it is clinically indicated.

• Test for asymptomatic bacteriuria early in pregnancy using dipstick testing; send MSU if indirect test is positive.
• Test for proteinuria every time BP is taken.
• Check for glycosuria at every visit, if more than 2 then test random plasma venous glucose and determine need for oral glucose tolerance test on basis of that result; there is no evidence of benefit from routine screening for gestational diabetes mellitus. See Glucose Tolerance Tests.

• Measure BP at presentation and at every subsequent appointment.
• Assess risk factors for pre-eclampsia:
  • Age >40
  • Family history
  • Previous history of pre-eclampsia
  • BMI >35 at presentation
  • Multiple pregnancy
  • Vascular disease e.g. hypertension, type 1 diabetes

Schedule further appointments accordingly to allow appropriate monitoring of BP.

Enquire into the areas listed below, and ask about any previous significant previous physical or psychiatric illness. Women with a history of significant psychiatric illness should be offered a referral to psychiatric services to screen for problems and advice on appropriate support.¹

• Occupation for any associated risks
• Smoking
• Alcohol and recreational drug use
• Domestic violence⁵
• Psychiatric illness

Advise and refer accordingly if any areas of concern come to light.

• Offer estimation of fetal size by measuring symphysis-fundal distance at each examination to look for fetus that is small or large for gestational age.
• After 36 weeks, palpate abdomen for possible malpresentation and confirm with US if suspected.

Offer a US examination early in pregnancy (preferably at 10–13 weeks) to:

• Determine gestational age
• Detect multiple pregnancies
• Help with later screening for Down's syndrome.
• At 11–14 weeks offer nuchal translucency screening for Down's syndrome with other tests if available.
• 18–20 weeks offer screening ultrasound for congenital anomalies.
• If placenta over the cervical os, offer a scan at 36 weeks for placenta praevia.

Women with the associated conditions below, or who have had the problems listed associated with previous pregnancies should be referred for obstetric or other advice as appropriate.¹ This list is not exhaustive:

• Cardiac disease, including hypertension
• Renal disease
• Diabetes treated with insulin or other endocrinological disorder
• Treated psychiatric disorder
• Haematological disease including propensity to thromboembolism and autoimmune disorder such as anti-phospholipid syndrome
• Epilepsy requiring anticonvulsant therapy
• Any current or recently treated malignant disease
• Significant respiratory impairment, including severe asthma
• Problematic alcohol use⁶
• Regular/problematic use of recreational drugs such as heroin, cocaine, crack, ecstasy etc.
• Chronic viral infections, e.g. HIV, HBV, HCV
• Autoimmune disorders
• Previous uterine surgery including caesarean section, myomectomy or cone biopsy
• BMI <18 or >30 kg/m²
• Women at higher risk of complications during pregnancy, e.g. older than 40 years, smokers, very young mothers, those without social support.
• Problems associated with previous pregnancies:
  • Recurrent miscarriage (>3 consecutive pregnancy losses or a mid-trimester loss)
  • Preterm birth
  • Severe pre-eclampsia, HELLP syndrome or eclampsia
  • Rhesus isoimmunisation or other significant blood group autoantibodies
  • Previous antepartum haemorrhage or postpartum haemorrhage on 2 occasions
  • Retained placenta on 2 occasions
  • Puerperal psychosis
  • Grand multiparity (>6 children)
  • Previous stillbirth or neonatal death
  • Small-for-gestational-age infant (<5th centile)
  • Large-for-gestational-age infant (>95th centile)
  • Baby weighing <2.5 kg or >4.5 kg
  • Baby with a structural or chromosomal anomaly