Routine Antenatal Investigations To Maintain Health During Pregnancy

Maintaining adequate health during pregnancy is important to avoid a range of common pregnancy complications. This article explains a number of routine antenatal investigations.

The National Institute for Clinical Excellence (2008) recommends that pregnant women undergo a routine full blood count at 12 weeks and again at 28 weeks gestation. A full blood count will indicate a woman’s ABO blood group - a knowledge of which is essential in the effective management of complications requiring rapid blood transfusion; white blood cell count - which may indicate the presence of infections with the potential to cause negative pregnancy outcomes; rubella immune status

- which may indicate the necessity of postpartum vaccination to safeguard future pregnancies against rubella-induced fetal malformations; platelet count - which may indicate the development of common pregnancy hypertensive conditions; haemoglobin levels; and Rhesus D status (DynaMed 2010; DynaMed 2011; DynaMed 2011/2).

A woman who is Rhesus negative and Rhesus antibody negative is at risk of developing Anti-D antibodies in response to Rhesus positive fetal blood, and of undergoing a negative autoimmune reaction against a future Rhesus positive fetus (Joanna Briggs Institute, 2011). In Rhesus negative and Rhesus antibody negative women, routine antenatal Anti-D prophylaxis has been shown to considerably reduce the risk of negative outcomes in subsequent Rhesus positive pregnancies (Crowther & Middleton, 2009). It is therefore recommended that such women receive Anti-D prophylaxis at 16, 28 and 32 weeks gestation (National Institute for Clinical Excellence, 2010).

Iron-deficiency anaemia, indicated by a haemoglobin count of under 10.5g/dL, is a common problem in pregnancy, is also indicated in a full blood count (Reveiz, Gyte & Cuervo, 2010). Anaemia increases the risk of a number of negative pregnancy outcomes, including altered fetal development resulting in low birthweight neonates (Haider & Bhutta, 2009). The midwife should recommend that such women commence daily non-teratogenic iron supplementation to promptly increase their haemoglobin levels to within the recommended parameters (Pena-Rosas & Viteri, 2009). Dietary improvements will also assist in allowing anaemic women to maintain healthy levels of iron throughout their pregnancy (Pena-Rosas & Viteri, 2009).

The other routine blood test offered to women screens for gestational diabetes mellitus. Optional blood tests - for uncommon infections, haemoglobinopathies and abnormal red blood cell alloantibodies, etc. - may be offered to a woman if her health history indicates that she may be at risk of such conditions

(National Institute for Clinical Excellence, 2008).

The other primary routine investigation offered to pregnant women is ultrasound examination at 6 to 8 weeks gestation - to determine precise gestational age and to detect multiple pregnancies; at a maximum of 20 weeks gestation - to screen for Down’s Syndrome, neural tube defects and fetal growth anomalies; and at a maximum of 32 weeks gestation - to assess fetal position, placental perfusion and amniotic fluid volume (National Institute for Clinical Excellence, 2008). Urinalysis - to screen for proteinuria, haematuria, bacteruria, keytonuria and glycosuria, etc. - is another routine antenatal investigation completed regularly from 12 weeks gestation (Grigg, 2009).

Non-routine antenatal investigations, to be completed only when indicated, include cardiotocograph, chorionic villius sampling and fetal blood sampling (Viccars, 2009).

SEE ALSO: Induction of Labour for Prolonged Pregnancy: What to Expect at an Antenatal Appointment: Common Pregnancy Problems and Ways to Reduce the Risk of Pregnancy Complications: SOURCES
Crowther, C. A. & Middleton, P. (2009). Anti-D administration in pregnancy for preventing rhesus alloimmunisation. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD000020.; DynaMed. (2010). Asymptomatic bacteriuria [DynaMed Summary]; DynaMed. (2011). Postpartum haemorrhage [DynaMed Summary]; DynaMed. (2011/2). Screening and monitoring during pregnancy [DynaMed Summary]; Grigg, C. (2009). Working with women in pregnancy. In Pairman, S., Pincombe, J., Thorogood, C. & Tracy, S. (Eds.). Midwifery: preparation for practice. UK: Churchill Livingstone Elsevier; Haider, B.A. & Bhutta, Z.A. (2009). Multiple micronutrient supplementation for women during pregnancy. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD004905.pub2; Joanna Briggs Institute. (2011). Rhesus D negative women [Evidence based recommended practice]; National Institute for Clinical Excellence. (2008). Routine antenatal care for healthy pregnant women [Evidence based recommended practice]; National Institute for Clinical Excellence. (2010). Pregnancy - routine anti-D prophylaxis for rhesus negative women [Evidence based recommended practice]; Pena-Rosas, J.P. & Viteri, F.E. (2009). Effects and safety of preventative oral iron or iron + folic acid supplementation for women during pregnancy. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD004736.pub3; Reveiz, L., Gyte, G.M.L., & Cuervo, L.G. (2010). Treatments for iron-deficiency anaemia in pregnancy. Cochrane Database of Systemic Reviews (Online). doi: 10.1002/14651858.CD003094.pub2; Viccars, A. (2009). Antenatal Care. In Fraser, D.M. & Cooper, M.A. (Eds.). Myles Textbook for Midwives (pp. 263-287). UK: Churchill Livingstone Elsevier.

Article Written By L K McCosker

L K McCosker is a blogger at

Last updated on 27-07-2016 841 0

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