Amniotic Fluid Dynamics by Akin Barry MBHD Paxton

Amniotic fluid dynamics

1. AMNIOTIC FLUID DYNAMICS Contents Definition Introduction Amniotic Fluid Production and Elimination Amnitic Fluid Assessment Disorders of Amniotic Fluid Volume Conclusion Reference

2. Introduction Dynamics refers to changes in progress and amniotic fluid dynamics refers to changes that occurs with amniotic fluid as pregnancy advances. Amniotic fluid is essential to the fetus and the maternal wellbeing. Therefore disruption in its dynamics affects both the fetus and the mother Amniotic fluid is an odorless, transparent or yellowish colored fluid inside the uterus surrounding the fetus Amniotic fluid acts as a cushion between the umbilical cord and the fetus, there by reducing the compression risk between the uterine wall and the fetus Also act as a reservoir for the fetus a sit contains essential antibodies, nutrients, and hormones for the mother. It also has antibacterial properties that protects the baby from infection. Amniotic fluid physically protects the fetus in cases of any abdominal trauma that occurs to the mother.

3. AMNIOTIC FLUID DYNAMICS Amniotic fluid predominantly consist of water (98-99%) during the first half of pregnancy, but gradually as gestational age increases the larger portion is made up of baby's urine alongside nutrients and antibodies. Amniotic fluid dynamic consist of two phase, that is production and elimination phase. Amniotic Fluid Production During the first half of pregnancy: During the first half of pregnancy, the amniotic fluid is obtained from maternal and fetal compartment. The water arrive across from the mother circulation and amniotic fluid present during early pregnancy is similar to maternal and fetal plasma but low proteins . During the Second half of pregnancy: During the second half of pregnancy fetal Urine starts entering the amniotic sac, pulmonary fluid secretion (through fetal respiration). Amniotic Fluid Removal Fetal swallowing: During fetal swallowing the amniotic fluid is absorbed through the gastrointestinal system of the fetus which is either removed through the placenta or filtered by the baby's kidneys. Through the placental Through the respiratory Tract.

4. AMNIOTIC FLUID ASSESSMENT The amniotic fluid index is use to measure the amniotic fluid sufficiency in pregnancy and is done with aid of ultrasound. A standard amniotic fluid index ranges from 5cm to 25cm or 500ml to 1000ml. The average AFI increases steadily in early gestation reaching a peak around 33 weeks where there is little change in volume till 39 weeks where the AFI decreases sharply Amniotic Fluid Volume relate to getational age At 12 week = 50ml At 20 weeks= 400ml At 36-38 weeks =1000ml (peak) At term=600ml-800ml At 43 weeks=200ml Factors Affecting AFI Nulliparous women in a research were observed to have significantly lower AFI than parous women. Racial and ethnic group.

5. DISORDERS OF AMNIOTIC FLUID VOLUME POLYHYDIAMNIOS Its is an amount of amniotic fluid more than 2000ml or AFI of greater than 25cm. Its divided into mild, moderate and severe . Mild AFI 25-29.9 cm Moderate AFI 30-34 cm Severe AFI>/= 35 cm. Etiology : increase production and decreased consumption of amniotic fluid will results in polyhydramnios Foetal Causes Congenital abnormality e,g Anencephaly, atresia. Increased placental mass Uniovular twin (monozygotic twin) Maternal causes Diabetes mellitus Pregnancy induced hypertension Clinical Picture Symptoms : Abdominal discomfort and pains Presure symptoms, dyspnea, palpitation, indigestion, edema and varicosities of the lower limbs

6. Sings On generalized examination over dissented abdomen Palpation of fundal level is higher than gestational age Uterus is tense cystic Feotal part are felt with difficulty Malpresentation and non engagement are common Auscultation of FHR is faint Investigation: Ultrasonography Management During Pregnancy Termination of pregnancy by high artificial rupture of membranes if foetus is death or malformed If healthy, rest, salt restriction and treatment of underlying cause such as diabetes or hypertension should be done Amniocentesis (Not done in our setting) 2 During Labour During labour when the cervix is half way dilated AROM is done and close monitoring of fetal heart rate

7. Complication Of Polyhydramnios Maternal During pregnancy Abortion Preterm labor Pregnancy induced hypertension Pressure symptoms Malpresentation During Labor Premature rupture of membranes Cord prolapse Abruptio placentae Shock Postpartum hemorrhage Feotus

8. Prematurity Asphyxia Malformation Oligohydramnios Reduction of amniotic fluid volume below 500ml or an AFI/=5cm Etiology: Oligohydramnios can be caused by the following:- Congenital abnormalies that affects your baby's kidneys o urinary tract Placental insufficiency Post date pregnancy Hypertension or preeclampsia Diabetes Dehydration Twin-to-twin transfusion syndrome

9. Clinical Picture Uterus is small for date The fetus is in hyper flexed altitude and breech presentation is common Management of Oligohydramnios Patient may be managed as in patient or out patient. If managed as out patient , fetal status should be monitored once or twice a week with ultrasound measurements and non stress test. Ultrasound to measure fetal growth should be done every 2 or 4 weeks (every 2weeks if growth is restricted) IOL is mostly recommended as early as 36 to 37 weeks for uncomplicated oligohydramnios. Complication Of Oligohydramnios Abnormal fetal development Poor or undeveloped lungs in fetus due to congenital abnormalities Still birth Infection if the bag of water is leaking Preterm birth

10. Miscarriage conclusion Amniotic fluid is dynamic through out pregnancy which is essential for the fetus wellbeing. Therefore an average amniotic fluid is essential for the growth and development of the fetus. Refernces American college of obstetrician and Gynenacologist (ACOG) 2021 American journal of Obstetrics and gynenacologist current concept of amniotic fluid dynamics