Amniocentesis

Before the procedure, patients should:

• Obtain a referral letter from their treating physician
• Register with a genetics laboratory and coordinate testing
• Collect the sample container from the genetics lab
• Complete and sign the informed consent form (by both partners)
• Stop taking Aspirin 72 hours before and Heparin 24 hours before the procedure (if prescribed)
• Undergo ultrasound to confirm fetal viability, placental location, fetal position, fetal measurements, and amniotic fluid assessment
• Shower and shave the abdominal area
• Fasting is not required
• Remove jewelry, watches, hair accessories, and personal items before entering the procedure room
• Avoid makeup, nail polish, dentures, contact lenses, hearing aids, or artificial nails
• Empty the bladder immediately before the procedure

 

How Amniocentesis is Performed

• The patient lies on a flat table. The abdomen is cleaned with an antiseptic solution and draped.
• Using continuous ultrasound guidance, the physician inserts a thin, long needle through the abdominal wall into the uterus, away from the placenta and fetus.
• A small amount of amniotic fluid is withdrawn into a syringe and sent to the genetics laboratory.
• A follow-up ultrasound is performed immediately afterward to check the fetal heartbeat and ensure fetal well-being.

 

Anesthesia:

• General anesthesia is not required. The patient remains awake.
• In anxious patients, or if sampling is needed from the lower uterus, local anesthesia may be given.
• Local anesthesia numbs only the skin entry site. Mild discomfort or cramping may still be felt when the needle passes through the uterine muscle.

Possible immediate side effects:

• Mild uterine cramps
• Light spotting
• Minor leakage of amniotic fluid through the vagina

 

Aftercare Following Amniocentesis

Medications:

• Progesterone injection, if prescribed
• Anti-D immunoglobulin (300 mcg) for Rh-negative mothers with Rh-positive partners
• Antibiotics, if prescribed
• Pain relievers, if needed

On the day of the procedure:

• You may eat and drink normally. Drink plenty of fluids (water or juice every 1–2 hours) to replace lost fluid and reduce cramping
• You may shower
• Avoid heavy activity; rest in bed (sitting or lying) for the remainder of the day
• Do not drive, exercise, lift heavy objects, take long walks, or have sexual intercourse
• Mild abdominal, pelvic, or back discomfort is common
• Light spotting may occur and last up to 2 days. Use only sanitary pads (not tampons)

The next day:

• If you feel well, you may return to work and resume daily activities

For 3 days (72 hours) after the procedure:

• Avoid strenuous physical activity or sports
• Avoid sexual intercourse
• Do not lift heavy objects
• Do not use bathtubs or swimming pools
• Avoid long-distance travel for 5–7 days

 

When to Contact Your Doctor

Seek immediate medical attention if you experience:

• Heavy leakage of amniotic fluid
• Heavy vaginal bleeding (heavier than a menstrual period)
• Fever or chills above 38°C
• Severe abdominal cramps
• Foul-smelling vaginal discharge

 

Risks and Complications

Amniocentesis is generally safe, but possible risks include:

• Premature rupture of membranes
• Direct injury to the fetus
• Maternal infection
• Miscarriage: Risk is about 0.2–0.3% when performed by an experienced specialist under ultrasound guidance. Most miscarriages occur within 4 weeks after the procedure.
  Risk factors include: less experienced operator, repeated attempts, elevated maternal AFP, fetal anomalies, vaginal bleeding during pregnancy, or history of ≥3 miscarriages.
• Transmission of maternal infections (e.g., Hepatitis, CMV, Toxoplasmosis, HIV): In such cases, alternative tests like cell-free DNA are preferred.
• Rarely, contamination by intestinal bacteria if the needle punctures the bowel, leading to infection, miscarriage, or septic shock
• Amnionitis (infection of amniotic fluid):  very rare
• Leakage of amniotic fluid (usually resolves within 1 week and is replaced within ~3 weeks)
• Separation of the amnion from the chorion (rare; usually no impact on pregnancy outcome)
• Indirect fetal complications (respiratory or orthopedic issues), especially if the procedure is done before 15 weeks or if prolonged leakage occurs.
• Cell culture failure (~0.1%), requiring repeat sampling
• Mosaicism (0.1–0.2%), requiring fetal blood sampling and genetic consultation