Oxford Handbook of Midwifery (45 page)

1. • Miscarriage
     
   • Stillbirth
     
   • Growth problems
     
   • Blindness
     
   • Brain damage
     
   • Epilepsy
     
   • Deafness.
     

     Prevention is the best strategy. Women may be offered pyrimethamine or sulfadiazine to limit transmission of the infection.
     

     Advise pregnant women to:
     

   • Cook all meat thoroughly until there are no pink areas and the juices are clear
     
   • Wash hands, utensils, and surface areas after preparing raw meat
     
   • Wash soil from fruit and vegetables before eating
     
   • Always use gloves when gardening and wash hands afterwards
     
   • Ask someone else to clean litter trays if a cat owner, or to wear gloves and wash hands thoroughly afterwards.
     

     

     1. National Institute for Health and Clinical Excellence (2008). Antenatal care: routine care for the healthy pregnant woman. Clinical guideline 62. London: NICE. Available at: M http://guidance. nice.org.uk/CG62.
        
     2. Guerra B, Ghi T, Quarta S,
        et al
        . (2006). Pregnancy outcome after early detection of bacterial vaginosis.
        European Journal of Obstetrics and Gynecology and Reproductive Biology
        128
        , 40–453.
        
     3. Blas MM, Canchihuaman FA, Alva IE, Hawes SE (2007). Pregnancy outcomes in women infected with
        Chlamydia trachomatis
        : a population-based cohort study in Washington State.
        Sexually Transmitted Infections
        83
        , 314–18.
        
     4. Pettersson K (2007). Perinatal infection with Group B streptococci.
        Seminars in Fetal and Neonatal Medicine
        12
        , 193–7.
        
     5. Brocklehurst P (2002). Antibiotics for gonorrhoea in pregnancy.
        Cochrane Database of Systematic Reviews
        2
        , CD000098.
        
     6. Walker GJA (2001). Antibiotics for syphilis diagnosed during pregnancy.
        Cochrane Database of Systematic Reviews
        2001,
        3
        , CD001143.
        
     7. Royal College of Obstetrics and Gynaecologists (2007).
        Management of Genital Herpes in Pregnancy
        . Green Top Guideline 30. London: RCOG Press.
        
     8. Chang M-H (2007). Hepatitis B virus infection.
        Seminars in Fetal and Neonatal Medicine
        12
        , 160–7.
        
     9. Royal College of Obstetrics and Gynaecologists (2007).
        Chickenpox in Pregnancy.
        Green Top Guideline 13. London: RCOG Press.
        

     This page intentionally left blank
     

     CHAPTER 9
     Pregnancy complications
     

     168‌‌
     

     Intrauterine growth restriction
     

     Growth restriction is failure of the fetus to reach normal growth param- eters.
     ¹
     This refers to a fetus that is less than the 10th percentile for its gestational age. Clinical measurement is often unreliable but if growth restriction is suspected the mother should be referred to the obstetrician for confirmation.
     

     Causes of intrauterine growth restriction
     

     Maternal factors which might influence fetal growth
     

   • Alcohol abuse
     
   • Smoking
     
   • Substance misuse
     
   • Poor nutrition
     
   • Hypertensive disorders
     
   • Maternal cardiac or renal disease.
     

     Pregnancy factors which might influence fetal growth
     

   • Multiple pregnancies (twins, triplets, etc.)
     
   • Placenta problems
     
   • Preeclampsia or eclampsia
     
   • Intrauterine infection
     
   • High altitudes.
     

     Monitoring growth
     

   • In the third trimester, ultrasound scans can be used to measure growth of the fetus if the clinical findings give cause for concern.
     
   • It is important to recognize large for gestational age as well as growth- restricted fetuses.
     
   • The two most common measurements used in monitoring growth are
     the head and abdominal circumferences.
     
   • The abdominal circumference is a useful when assessing growth,
     

     because of fat deposition in the fetal liver. This is reduced in growth- restricted fetuses and increased in macrosomic fetuses. The ratio between the head and abdominal circumference helps distinguish between the two types of growth restriction:
     

     • Asymmetrical growth restriction
       
     • Symmetrical growth restriction.
       

       Asymmetrical growth restriction
       

   • This is characterized by falling abdominal circumference measurements but the head circumference stays within normal limits.
     
   • This is referred to as ‘brain sparing’, as the brain continues to receive nutrients and continues to develop while the fat and glycogen deposits in the liver dwindle as the fetus is compromised.
     
   • It is usually apparent in the later stages of pregnancy and is due to placental insufficiency.
     
   • This is a sign that the oxygen supply to the fetus will slow down in the near future.
     

INTRAUTERINE GROWTH RESTRICTION

169

Symmetrical growth restriction

It is often difficult to distinguish between the growth restricted and merely small fetus. The cause may be attributed to incorrect dates and the woman given a revised date of delivery. Measurements taken from the early pregnancy scan are therefore essential to avoid induction of labour that is either too early or too late.

1
Baschat AA, Galan HL, Ross MG, Gabbe SG (2007). Intrauterine growth restriction. In: Gabbe SG, Niebyl JR, Simpson JL (eds)
Obstetrics: Normal and Problem Pregnancies.
5th edn. Philadelphia, PA: Elsevier Churchill Livingstone.

CHAPTER 9
Pregnancy complications

170‌‌

Multiple pregnancy

Incidence

In natural conceptions 1:80 result in twin pregnancy. 1:6400 conceptions results in triplets, and 1:512 000 results in quadruplets. The incidence of multiple pregnancies overall is on the increase due to the impact of suc- cessful infertility treatment.

Where an average incidence of triplets in a maternity unit delivering 3000 babies a year might result in a triplet birth every 2 years, it is becoming more common to see two to three such births in a year.

Twin pregnancy has the highest incidence and can be divided into two types:

Monozygotic
—sometimes referred to as identical twins. The incidence is 2.5–4 per 1000 births.

• Results from one ova and one spermatozoa.
  
• There is one chorion membrane and one placenta.
  
• There are two amnion, one for each twin.
  
• The babies are always the same sex, blood group, eye colour, etc.
  

  Dizygotic or non-identical twins
  . The incidence is more frequent with hered- itary factors from both the mother and father affecting the frequency.
  ¹
  

• Results from two ova and two spermatozoa.
  
• There are two chorion and two placenta though these may be so closely joined that they look like one.
  
• There are two amnion, one for each twin.
  
• The babies may be the same sex or one of each, and no more alike than any other family members.
  

  Diagnosis is invariably made at the time of the dating scan early in the second trimester. By 20 weeks the uterus will be large for gestational age
  

  and this is obvious on palpation. If a mother is late booking or has not received antenatal care the diagnosis may be made quite late in pregnancy.
  

  It is rare nowadays to diagnose twins only once the mother is in labour.
  

  Special considerations
  

  Serum screening tests for fetal abnormality are unsuitable as the results will be unreliable. Nuchal translucency scans, placental biopsy or amnio- centesis are options the mother may wish to consider.
  

  During pregnancy the mother has a higher risk of complications developing such as:
  

• Miscarriage
  
• Exaggerated minor disorders of pregnancy
  
• Premature labour
  
• Pregnancy induced hypertension
  
• Anaemia—due to the demands of two fetuses.
  
• Polyhydramnios—excess amounts of amniotic fluid
  
• Placental abruption
  
• Placenta praevia
  
• Intrauterine growth restriction.
  

MULTIPLE PREGNANCY

171

Antenatal management