Maternal conditions affecting the fetus Flashcards
- *Maternal conditions affecting the fetus
- Diabetes mellitus***
- Poorly-controlled maternal diabetes is associated with polyhydramnios and pre-eclampsia, increased rate of early fetal loss, congenital malformations and late unexplained intrauterine death.
- Ketoacidosis carries a high fetal mortality
Fetal problems associated with maternal diabetes are:
- Congenital malformations. Overall, there is a 6% risk of congenital malformations, a three-fold increase compared with the non-diabetic population
- Intrauterine growth restriction (IUGR). There is a three-fold increase in growth restriction in mothers with long-standing microvascular disease
- Macrosomia
Maternal conditions affecting the fetus
Neonatal problems include
- Hypoglycaemia. Transient hypoglycaemia common during first day of life from fetal hyperinsulinism, often prevented by early feeding
- Respiratory distress syndrome (RDS). More common as lung maturation is delayed
- Hypertrophic cardiomyopathy. Hypertrophy the cardiac septum occurs in some infants. Regresses over several weeks but may cause heart failure from reduced left ventricular function
- Polycythaemia (venous haematocrit >0.65). Makes the infant look plethoric. Treatment with partial exchange transfusion to reduce the haematocrit and normalise viscosity may be required.
Maternal conditions affecting the fetus
Gestational Diabetes
- when carbohydrate intolerance occurs only during pregnancy
- more common in women who are obese and in those of Afro-Caribbean and Asian ethnicity
- incidence of macrosomia and its complications is similar to that of the insulin-dependent diabetic mother
- increasing number of mothers with type 2 non-insulin dependent diabetes, associated with the increase in obesity.Fetuses increased risk of congenital malformations.
Maternal conditions affecting the fetus
Hyperthyroidism
Systemic lupus erythematosus
Autoimmune thrombocytopenic purpura
Hyperthyroidism
- If mothers have had Graves’ disease, 1–2% of their newborn infants are hyperthyroid, due to circulating thyroid-stimulating antibody, which crosses the placenta and stimulates the fetal thyroid.
- Hyperthyroidism in the fetus is suggested by fetal tachycardia on the CTG trace, and fetal goitre may be evident on ultrasound; in the neonate it is suggested by irritability, weight loss, tachycardia, heart failure, diarrhoea and exophthalmos.
Maternal conditions affecting the fetus
Systemic lupus erythematosus
Systemic lupus erythematosus
- Systemic lupus erythematosus (SLE) with antiphospholipid syndrome is associated with recurrent miscarriage, intrauterine growth restriction, pre-eclampsia, placental abruption and preterm delivery.
- Some of the infants born to mothers with antibodies to the Ro (SS-A) or La (SS-B) antigens develop neonatal lupus syndrome, in which there is a self-limiting rash and, rarely, heart block.
Maternal conditions affecting the fetus
Autoimmune thrombocytopenic purpura
- In maternal autoimmune thrombocytopenic purpura (AITP), the fetus may become thrombocytopenic because maternal IgG antibodies cross the placenta and damage fetal platelets.
- Severe fetal thrombocytopenia places the fetus at risk of intracranial haemorrhage following birth trauma.
- Infants with severe thrombocytopenia or petechiae at birth should be given intravenous immunoglobulin.
- Platelet transfusions may be required if there is acute bleeding
Maternal drugs affecting the fetus
- While the teratogenicity of a drug may be recognised if it causes malformations which are severe and distinctive, as with limb shortening following thalidomide ingestion, milder and less distinctive abnormalities may go unrecognised.
Maternal drugs affecting the fetus
Alcohol and smoking
- Excessive alcohol ingestion during pregnancy is sometimes associated with the ‘fetal alcohol syndrome’
- clinical features are growth restriction, characteristic face, developmental delay and cardiac defects (up to 70%)
Maternal conditions affecting the fetus
Congenital infections
Intrauterine infection is usually from maternal primary infection during pregnancy. Those that can damage the fetus are:
- Rubella
- Cytomegalovirus (CMV)
- Toxoplasma gondii
- Parvovirus
- Varicella zoster
Maternal conditions affecting the fetus
Congenital infections
Rubella
- diagnosis of maternal infection must be confirmed serologically as clinical diagnosis is unreliable
- risk and extent of fetal damage are mainly determined by the gestational age at the onset of maternal infection
- Infection before 8 weeks’ gestation causes deafness, congenital heart disease and cataracts in over 80%
- About 30% of fetuses of mothers infected at 13–16 weeks’ gestation have impaired hearing
- beyond 18 weeks’ gestation, the risk to the fetus is minimal.
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Maternal conditions affecting the fetus
Congenital infections
Diagnosis of congenital rubella, cytomegalovirus (CMV) and Toxoplasma infection
Mother
- Seroconversion on screening serology
Fetus
- Amniocentesis or chorionic villus sample, PCR
Placenta
- Microscopy for syphilis, PCR
Urine from infant
- Rubella, CMV – culture, PCR
Blood, CSF, other samples from infant
- Culture, PCR
Blood serology
- Rubella-specific IgM, CMV-specific IgM, Toxoplasma-specific IgM
Maternal conditions affecting the fetus
Congenital infections
Cytomegalovirus
- most common congenital infection, affecting 3–4/1000 live births in the UK
- About 1% of susceptible women will have a primary infection during pregnancy, and in about 40% of them the infant becomes infected
When an infant is infected:
- 90% are normal at birth and develop normally
- 5% have clinical features at birth, such as hepatosplenomegaly and petechiae (Fig. 9.6b), most of whom will have neurodevelopmental disabilities such as sensorineural hearing loss, cerebral palsy, epilepsy and cognitive impairment
- 5% develop problems later in life, mainly sensorineural hearing loss.
Maternal conditions affecting the fetus
Congenital infections
Toxoplasmosis
- Acute infection with Toxoplasma gondii, a protozoan parasite, may result from the consumption of raw or undercooked meat and from contact with the faeces of recently infected cats
- . Transplacental infection may occur during the parasitaemia of a primary infection, and about 40% of fetuses become infected
Features:
- Retinopathy, an acute fundal chorioretinitis which sometimes interferes with vision
- Cerebral calcification
- Hydrocephalus.
Infected newborn infants are usually treated (pyrimethamine and sulfadiazine) for 1 year. Asymptomatic infants remain at risk of developing chorioretinitis into adulthood.
Maternal conditions affecting the fetus
Congenital infections
Varicella zoster
15% of pregnant women are susceptible to varicella (chickenpox). Usually, the fetus is unaffected but will be at risk if the mother develops chickenpox:
- in the first half of pregnancy (<20 weeks), when there is a <2% risk of the fetus developing severe scarring of the skin and possibly ocular and neurological damage and digital dysplasia
- within 5 days before or 2 days after delivery, when the fetus is unprotected by maternal antibodies and the viral dose is high. About 25% develop a vesicular rash. The illness has a mortality as high as 30%.
- Exposed susceptible mothers can be protected with varicella zoster immune globulin (VZIG) and treated with aciclovir. Infants born in the high-risk period should also receive zoster immune globulin and are often also given aciclovir prophylactically
Maternal conditions affecting the fetus
Congenital infections
Syphilis
- Congenital syphilis is rare in the UK.
- Those specific to congenital syphilis include a characteristic rash on the soles of the feet and hands and bone lesions.
- If mothers with syphilis identified on antenatal screening are fully treated 1 month or more before delivery, the infant does not require treatment and has an excellent prognosis.
- If there is any doubt about the adequacy of maternal treatment, the infant should be treated with penicillin.
