Oligohydramnios - is an abnormally small amount of amniotic fluid. At term there may be 300–500 ml but amounts vary and they can be even less. in the first half of pregnancy, oligohydramnios is ofen found to be associated with @ renal agenesis (absence of kidneys) or Potter's syndrome, in which the baby also has pulmonary hypoplasia. at any time in pregnancy before 37 weeks, oligohydramnios may be due to @ fetal malformation @ preterm prelabour rupture of the membranes (PPROM)where the amniotic fluid fails to re- accumulate.
The lack of amniotic fluid reduces the intrauterine space and will cause compression malformations. The baby has a squashed-looking face, flattening of the nose, micrognathia (a malformation of the jaw) and talipes. dry skin leathery in appearance. -Oligohydramnios can accompany maternal dehydration, and sometimes occurs in post- term pregnancies
Diagnosis -On inspection, the uterus may appear smaller than expected for the period of gestation. - a reduction in fetal movements ,if she is a multigravida and has experienced childbirth previously. -On palpation, the uterus is small and compact and fetal parts are easily felt. -Ultrasonic scanning will enable differentiation of oligohydramnios from intrauterine growth restriction (IUGR). Renal malformation may be visible on the scan. Auscultation of the fetal heart should be heard without any undue difficulty.
Management -This will depend on @ the gestational age @ the severity of the oligohydramnios @ the cause of the oligohydramnios. -In the 1st trimester the pregnancy is likely to miscarry. - in the 2nd trimester associated with fetal death and congenital malformations.
- In the 3rdtrimester associated with (PPROM) and birth is usually indicated -Liquor volume will be estimated by ultrasound scan and the woman should be questioned about the possibility of pre-term rupture of the membranes. Doppler ultrasound of the uterine artery to assess placental function,. If the woman is dehydrated she should be encouraged to drink plenty of water, or offered intravenous hypotonic fluid.
- prophylactic amnioinfusion -Where fetal anomaly is not considered to be lethal - the cause of the oligohydramnios is not known Benefits of amnioinfusion : -to prevent compression malformations -to avoid hypoplastic lung disease -to prolong the pregnancy.
- the woman should be observed for uterine infection (chorioamnionitis), and treated - near-term and term pregnancy : IOL. -CTG, is desirable because of the potential for impairment of placental circulation and cord compression - ultrasound to determine amniotic fluid measurement -Doppler assessment of fetal and uteroplacental arteries - epidural analgesia may be indicated because uterine contractions can be unusually painful due to the lack of amniotic fluid. N.B; if meconium is passed in utero represent a greater danger to an asphyxiated fetus during birth.
Preterm prelabour rupture of the membranes (PPROM) - before 37 weeks' gestation -the fetal membranes rupture -without uterine activity -No cervical dilatation.
Incidence & prevalence : -placental abruption could be occur to women who present with PPROM. - recurrence rate in subsequent pregnancies - a strong association between PPROM and maternal colonization (Bacterial vaginosis [BV]),pathogenic micro-organisms, may develop to chorioamnionitis -Infection may both precede (and cause) or follow PPROM. - common in smokers -use of recreational drug - cocaine users. - 40% of preterm births due to PPOM
Risks of PPROM labor resulting in a preterm birth chorioamnionitis, may develop to fetal and maternal systemic infection if not treated oligohydramnios if prolonged PPROM occurs cord prolapse malpresentation associated with prematurity antepartum haemorrhage neonatal sepsis psychosocial problems resulting from 1-uncertain fetal and neonatal outcome 2- long- term hospitalization 3- increased incidence of impaired mother and baby bonding after birth
Management - admitted to the maternity unit. - history is taken -PPROM is confirmed by a sterile speculum, examination of any pooling of liquor in the posterior fornix of the vagina. - Saturated sanitary towels over a 6-hour period will also offer diagnosis - urine leakage should be excluded. -A Nitrazine test .
-A fetal fibronectin immunoenzyme test مهم confirming rupture of the membranes - ultrasound scanning. - avoid Digital vaginal examination to reduce the risk of introducing infection. monitoring fetal heart rate, as an infected fetus may have a tachycardia v\s to detect a maternal infection, temperature and pulse assess uterine tenderness observe any purulent or offensively smelling vaginal discharge.
-If 1- the pregnancy is less than 32 weeks 2- the fetus appears to be uncompromised 3- APH and labour have been excluded, Management should be admission to hospital. ultrasound scans to @assess the growth of the fetus @assess the extent of ruptured membrane @any complications.
Corticosteroids to mature the fetal lungs as soon as PPROM a tocolytic drug (such as atosiban acetate) to prolong the pregnancy. vaginal infections are treated with antibiotics. Prophylactic antibiotics may also be offered to women without symptoms of infection. If membranes rupture before 24 weeks of gestation the outlook is poor and the woman may be offered termination of the pregnancy.
If the woman is more than 32 weeks pregnant, the fetus appears to be compromised and APH or intervening labour is suspected or confirmed, active management will ensue. The mode of birth will induction of labour or caesarean section . -Hindwater leakage of amniotic fluid, and resealing of the amniotic sac are currently poorly understood phenomena