COMPREHENSIVE OBSTETRICS: Key Concepts

1. STANDARD DEFINITIONS

Gravida

• Primigravida: first pregnancy (G1)
• Multigravida: G2-G4
• Grand Multigravida: G5 or more

Para (Parity)

• Primipara: P1
• Multipara: P2-P4
• Grand Multipara: P5 or more

Note: Twin or multiple pregnancies count as ONE delivery for parity (not two). The GTPAL system is more detailed: G = gravida, T = term deliveries (>37 weeks), P = preterm deliveries (20-37 weeks), A = abortions/losses <20 weeks, L = living children.

Abortion (Standard Definition)

• Spontaneous abortion (miscarriage): Naturally occurring pregnancy loss before 20 weeks (US definition) or <22 weeks (WHO)
• Induced abortion: Deliberate termination of pregnancy
• Threatened, inevitable, incomplete, complete, missed, septic subtypes are recognized

Live Birth (WHO Definition)

Stillbirth (WHO Definition)

• For international reporting purposes: WHO recommends reporting stillbirths of 28 or more completed weeks gestation.
• The WHO stillbirth page states: "A baby who dies after 28 weeks of pregnancy, but before or during birth, is classified as a stillbirth."
• Early stillbirth: 22-27+6 weeks | Late stillbirth: 28-36+6 weeks | Term stillbirth: ≥37 weeks

2. COMPLICATIONS OF YOUNG AGE IN PREGNANCY

Teenage Pregnancy (< 18 years, more specifically < 16 years)

• Anemia (nutritional deficiency - iron, folate)
• Pregnancy-induced hypertension (PIH) and pre-eclampsia (higher risk, especially < 16 years)
• Cephalopelvic disproportion (CPD) due to immature pelvis
• Prolonged and obstructed labor
• Higher rate of operative deliveries (instrumental, cesarean section)
• Postpartum hemorrhage (PPH)
• Nutritional deficiencies (poor dietary intake)
• Sexually transmitted infections (STIs)
• Increased risk of pregnancy-induced hypertension
• Higher incidence of low weight gain
• Psychological problems, social problems, poor compliance with ANC

• Low birth weight (LBW) and small for gestational age (SGA)
• Preterm birth
• Intrauterine growth restriction (IUGR)
• Higher perinatal mortality
• Higher neonatal mortality
• Congenital anomalies (relative risk)
• Increased NICU admissions

3. COMPLICATIONS OF OLD AGE IN PREGNANCY

Advanced Maternal Age (AMA): Age ≥ 35 years

• Elderly Primigravida: First pregnancy at age ≥ 35 years (term coined by Munro Kerr; some modern texts use "advanced maternal age primigravida")
• Very Advanced Maternal Age (VAMA): ≥ 40 years
• Extremely Advanced Maternal Age (EAMA): ≥ 45 years

• Gestational diabetes mellitus (GDM) - significantly higher risk
• Gestational hypertension and pre-eclampsia
• Placenta previa and placental abruption
• Antepartum hemorrhage
• Malpresentations
• Prolonged labor / dysfunctional uterine activity
• High cesarean section rate (both elective and emergency)
• Postpartum hemorrhage (PPH)
• Thromboembolic disease (DVT, pulmonary embolism)
• Higher rate of spontaneous miscarriage (due to chromosomal errors)
• Grand multiparity related complications in older multiparas: uterine atony, PPH, malpresentation

• Higher rate of chromosomal abnormalities: Down syndrome (Trisomy 21), Trisomy 18, Trisomy 13
  • Risk of Down syndrome at 35 years: ~1 in 350; at 40 years: ~1 in 100; at 45 years: ~1 in 30
• Intrauterine growth restriction (IUGR)
• Preterm birth
• Stillbirth (significantly higher in AMA)
• Low Apgar scores
• NICU admission
• Autism spectrum disorder (emerging evidence)
• Congenital anomalies (non-chromosomal also increased)

4. Rh INCOMPATIBILITY AND TREATMENT

Pathophysiology

• Occurs when an Rh-negative (D-negative) mother carries an Rh-positive fetus
• Fetal red blood cells (RBCs) cross the placenta (fetomaternal hemorrhage) during delivery, abortion, amniocentesis, or antepartum
• Mother's immune system generates anti-D IgM then IgG antibodies (sensitization)
• In subsequent Rh+ pregnancies, maternal anti-D IgG crosses the placenta, attaches to fetal RBCs → hemolysis → Hemolytic Disease of the Fetus and Newborn (HDFN) / Erythroblastosis Fetalis
• First pregnancy is usually safe (sensitization); subsequent pregnancies affected

Diagnosis / Investigation

• Maternal blood group and Rh typing at booking
• Indirect Coombs Test (ICT) = antibody screen in Rh-negative mother
• If ICT positive: antibody titration, fetal surveillance
• Doppler of Middle Cerebral Artery (MCA) peak systolic velocity - if >1.5 MoM, indicates fetal anemia
• Amniocentesis (optical density at OD450 - Liley's chart) - less used now
• Fetal blood sampling / cordocentesis for direct fetal Hb, Coombs test

Management

1. Anti-D Immunoglobulin (RhIg / RhoGAM)
   • Given to ALL non-sensitized (ICT-negative) Rh-negative women
   • Antenatal prophylaxis:
     • 28 weeks of gestation: 300 mcg IM (ACOG protocol)
     • Some protocols: 28 AND 34 weeks
     • WHO recommends antenatal prophylaxis at 28 and 34 weeks in non-sensitized Rh-negative women
   • Postnatal prophylaxis: 300 mcg within 72 hours of delivery of an Rh-positive baby
   • After sensitizing events: abortion, ectopic pregnancy, amniocentesis, CVS, antepartum hemorrhage, external cephalic version (ECV), trauma
     • Dose: 300 mcg (standard) or 50 mcg (for events <12 weeks)

   2024 ACOG/SMFM UPDATE: For spontaneous or induced abortion at less than 12 weeks, Rh testing and RhIg are NOT routinely indicated. They can be considered on an individual shared decision-making basis. This represents a change from previous guidelines. - ACOG 2024 Clinical Practice Update

2. Cell-free fetal DNA (cffDNA) / NIPT for fetal RHD genotyping: Now recommended (strong evidence) in Rh-negative women to determine if the fetus is truly Rh-positive before giving RhIg, especially during RhIg shortages. National Blood Authority 2024 Guideline

• Intrauterine transfusion (IUT): for severe fetal anemia (MCA-PSV >1.5 MoM); O-negative, CMV-negative, irradiated packed RBCs given into umbilical vein or intraperitoneal
• Early delivery: once fetal lung maturity achieved (~34-37 weeks based on severity)
• Neonatal treatment: Phototherapy, exchange transfusion, IV immunoglobulin (IVIG), top-up transfusions for HDN

5. OCCUPATIONAL COMPLICATIONS IN PREGNANCY

• Prolonged standing / heavy physical work: increased risk of preterm labor, LBW, miscarriage, varicose veins, backache, fatigue
• Shift work / night work: disrupted circadian rhythm; associated with preterm birth, LBW, menstrual disturbances
• Lifting and carrying heavy loads: uterine prolapse risk, preterm labor, musculoskeletal injuries
• Vibration (whole-body or hand-arm): associated with preterm labor and LBW
• Noise exposure: fetal hearing damage (cochlear), preterm birth (high levels)

• Organic solvents (paint, dry-cleaning): miscarriage, congenital malformations
• Lead (manufacturing): miscarriage, stillbirth, LBW, neurotoxicity to fetus
• Mercury (mining, fish industry): Minamata disease - severe neurological damage to fetus
• Pesticides / herbicides: increased risk of congenital anomalies, miscarriage
• Anesthetic gases (healthcare workers): miscarriage risk (now mitigated by scavenging systems)
• Cytotoxic drugs / chemotherapy agents (nurses/pharmacists): teratogenicity, miscarriage

• Rubella, CMV, Toxoplasma, Hepatitis B, Varicella, SARS-CoV-2, Parvovirus B19
• Ensure vaccination and appropriate PPE

• Ionizing radiation (radiology, nuclear medicine staff): fetal malformations, childhood malignancy
• Safe threshold: < 5 rad total exposure during pregnancy

• Women should avoid jobs with heavy lifting, chemical exposures, radiation, and prolonged standing
• Maternity leave rights apply: modified duties or temporary redeployment
• WHO and ILO recommend worksite risk assessments for pregnant workers

6. RELIGIOUS PRACTICES AND COMPLICATIONS IN PREGNANCY

• Ramadan fasting (Islam): prolonged daily fasting during pregnancy associated with LBW, reduced birth length, preterm birth (especially if in first trimester during summer), neonatal hypoglycemia. Islamic scholars permit breaking fast when medically necessary.
• Jain/Hindu fasting periods: similarly can lead to nutritional deficiencies (iron, folate, protein), anemia, IUGR
• Vegan/vegetarian religious diets: risk of B12 deficiency (neurological damage to fetus), iron-deficiency anemia, zinc deficiency, omega-3 deficiency
• Kosher / Halal food restrictions: generally less risky but may limit variety

• Jehovah's Witnesses: refuse blood products (whole blood, RBCs, plasma, platelets)
• This creates serious risk in obstetric hemorrhage (PPH, placenta previa, ruptured ectopic)
• Management: preoperative autologous blood donation, cell salvage intraoperatively, erythropoietin (EPO), iron supplementation, minimize blood loss; detailed advance directive discussions required
• Legal/ethical dilemmas arise especially if patient is unconscious

• Female genital mutilation (FGM): practiced in some African and Middle Eastern communities for religious/cultural reasons; associated with obstructed labor, perineal tears, vesicovaginal fistula, dystocia, C-section, PPH, psychological trauma

• Some traditional/religious herbal remedies are teratogenic (e.g., blue cohosh, pennyroyal, comfrey)
• Advise patients to disclose all herbal/traditional medicine use

• Some communities refuse prenatal genetic testing (amniocentesis, NIPT) for religious reasons
• Important to respect autonomy while providing full information

• Certain communities may delay cord clamping, insist on specific delivery positions, or engage traditional birth attendants - counsel appropriately

7. NAEGELE'S RULE - EDD CALCULATION

Definition

Formula

• Add 9 months = 1st October 2024
• Add 7 days = 8th October 2024 (EDD)

• A regular 28-day menstrual cycle
• Ovulation on day 14
• Normal gestational duration of 280 days (40 weeks) from LMP

Indications

• Regular menstrual cycles (28-day cycle)
• Known and certain LMP date
• No oral contraceptive use in preceding 3 months
• No recent miscarriage or delivery
• No hormonal irregularities

Contraindications / When Naegele's Rule is Inaccurate

• Irregular menstrual cycles (PCOS, oligomenorrhea)
• Unknown or uncertain LMP
• Recent use of OCP (ovulation may be delayed)
• Conception after recent delivery or miscarriage (no period yet)
• Lactational amenorrhea with conception
• Cycle length significantly different from 28 days (add or subtract days accordingly)
• In all these cases, first trimester ultrasound (Crown-Rump Length, CRL) is the gold standard for EDD

Important: When there is a discrepancy >7 days in first trimester ultrasound or >10-14 days in second trimester vs. Naegele-calculated EDD, the ultrasound EDD takes precedence.

8. PERIOD OF GESTATION - CALCULATION

Definition

Methods of Calculation

• Count from Day 1 of LMP to the current date
• Express as: X weeks + Y days
• e.g., LMP 1 January; current date 15 March = 10 weeks 3 days

• Period of Gestation = 40 weeks - (EDD - Current Date in weeks)
• e.g., EDD 8 October; current date 1 July = approx. 14 weeks remaining, so GA = 40 - 14 = 26 weeks

• First trimester: Crown-Rump Length (CRL) - most accurate (± 5-7 days)
• Second trimester: Biparietal Diameter (BPD), Head Circumference (HC), Abdominal Circumference (AC), Femur Length (FL) (± 2-3 weeks)
• Third trimester: least accurate (± 3-4 weeks)

Landmarks for Period of Gestation

9. BOOKING VISIT

Definition

Objectives of Booking Visit

1. Confirm pregnancy and estimate gestational age / EDD
2. Complete obstetric and medical history (GTPAL, past medical, surgical, family history)
3. Identify high-risk pregnancies (screen for risk factors)
4. Full physical examination (general, systemic, obstetric - uterine size, fundal height)
5. Baseline investigations
6. Initiate health promotion and counseling
7. Plan antenatal care schedule

Baseline Investigations at Booking

• Blood: Full blood count (FBC), blood group and Rh typing, ICT (Rh-negative), blood glucose (DIPSI / GCT), VDRL (syphilis), HIV testing, HbsAg (Hepatitis B), rubella serology, thyroid function (TSH), hemoglobin electrophoresis (if indicated)
• Urine: Routine analysis (protein, glucose, cells), urine culture
• Ultrasound: Dating scan (viability, CRL, EDD, nuchal translucency if 11-13+6 weeks)
• First trimester screening: Combined test - PAPP-A, free beta-hCG + NT scan (Down syndrome screening)

WHO Updated Definition of "Booked"

• "Antenatal care (ANC) can be defined as the care provided by skilled health-care professionals to pregnant women and adolescent girls in order to ensure the best health conditions for both mother and baby during pregnancy."
• WHO moved from a "visit" model to a "contact" model, emphasizing the quality and content of each contact.

• Booked: received at least 3 antenatal care visits (traditional definition used in many South Asian and African countries), OR has attended at least one visit at the institution where she is to deliver
• Unbooked: no antenatal care received during the current pregnancy

In Indian obstetric practice (and per FOGSI 2024 guidelines), a booked case = a woman who has had at least 3 antenatal visits and received at least one dose of tetanus toxoid (TT/Td) and at least one trimester of iron-folate supplementation.

Schedule of Antenatal Contacts (WHO 2016 - 8 Contact Model)

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