Amnioscopy (amniocentesis) is performed when a child is transferred.Normal pregnancy, calculated after the 1st day of the last menstrual period, lasts on average 280 days or 40+0 weeks of gestation (SSW). From an extension of 14 days, i.e. from 294 days or 42+0 SSW, one speaks according to WHO and FIGO (Fédération Internationale de Gynécologie et d’Obstétrique) of a temporal transfer. In the German-speaking world, the term “Terminüberschreitung” (missed due date) is commonly used for the period from 40+1 to 41+6 weeks of gestation [S1 guideline]. Transmission poses a risk to the unborn child because the risk of placental insufficiency (placental weakness) increases with transmission. As a result, there is a possibility that the unborn baby will not receive adequate oxygen (fetal hypoxia/oxygen deficiency of the unborn baby) and nutrients (macronutrients and micronutrients/vital nutrients).
Indications (areas of application)
- Detection of Vernix caseosa (also: amniotic fluid or cheese smear) in cases of unclear due date or anamnestic missed due date or transmission.
- Suspicion of premature rupture of the membranes or questionable amniotic fluid discharge.
- Exclusion of green amniotic fluid
The procedure
The examination is performed with the help of the so-called amnioscope. This is an illuminated rod that is passed through the vagina and the already slightly open cervix to the transparent amniotic sac (amnion). In this way, the doctor can check the appearance of the amniotic fluid.Amnioscopy is performed about every one to two days during the period of transfer.
Interpretation
The color of the amniotic fluid can provide important clues for normality or pathological (abnormal) situations.
- Clear amniotic fluid with vernix flocs = regular findings (normal findings).
- Green amniotic fluid is indicative of a condition following fetal hypoxia (oxygen deficiency of the unborn)Note: The green coloration is caused by the excretion of intestinal contents called puerperal fluid.
- Fresh blood admixture may be an indication of placental or fetal hemorrhage (bleeding through the placenta or unborn child)
- Foul-smelling, cloudy amniotic fluid is indicative of chorioamnionitis (inflammation of the inner egg membrane and outer layer of amniotic membranes around the embryo or fetus/unborn child)
Possible complications
- Opening of the amniotic sac (amniotic membrane) with leakage of amniotic fluid, resulting in induction of labor
- Induction of labor by manipulation of the cervix.
- Carrying germs from the vagina (in the case of vaginal infections), which can then lead to amniotic infection syndrome (AIS; infection of the chorion (egg cavity), placenta (placenta), membranes and possibly the fetus with risk of sepsis (blood poisoning) for the child).
Further notes
- Amniocopy, introduced by Saling in 1961, has been increasingly discouraged since about 2000 because of the high percentage (up to 57%) of false-negative findings, even in the most severe metabolic acidosis (32%). The rate of false-positive findings is reported to be as high as 95%. In a textbook published in 2020, a note appears that this examination should no longer be used if the deadline is missed.
- Missed deadline and transmission:
- According to a Cochrane analysis based on 34 randomized controlled trials, there was a significant reduction in perinatal mortality with a birth induction strategy starting at 37 weeks’ gestation (SSW) compared with a wait-and-see strategy (22 trials, 18,795 infants): perinatal deaths occurred in 4 cases in the birth induction group compared with 25 in the wait-and-see group (= relative risk reduction of 69%).
- Inducing labor after 42 weeks’ gestation in low-risk pregnancies (n = 2,760 women) resulted in higher perinatal mortality.
