Obstetric Topic 54. Obstetric statistics

I. Maternal Vital Statistics

Birth and Fertility

• Birth rate: number of births per 1000 total population in a given year.
• Fertility rate: number of live births per 1000 women of reproductive age, classically 15-44 or 15-49 years depending on dataset.

Maternal Mortality

• Maternal mortality ratio (MMR): maternal deaths during pregnancy, childbirth or within 42 days of termination / live births × 100,000.
• Maternal death: death of a woman while pregnant or within 42 days after pregnancy ends, from a cause related to or aggravated by pregnancy or its management.
• Excluded: accidental or incidental deaths not related to pregnancy.

1. Direct maternal death: caused by obstetric complications of pregnancy, labor, delivery or puerperium.
2. Indirect maternal death: caused by pre-existing or newly developed non-obstetric disease aggravated by pregnancy physiology.
3. Late maternal death: pregnancy-related death after 42 days but before 1 year postpartum; usually recorded separately.

• Common direct causes: hemorrhage, hypertensive disorders/eclampsia, sepsis, embolic events.
• Common indirect causes: cardiac disease, diabetes, respiratory disease, cancer and other medical disorders aggravated by pregnancy.

II. Fetal and Neonatal Mortality

Key Time Periods

• Abortion / miscarriage: fetal loss before viability; in this project/source system, before GW24.
• Stillbirth / late fetal death / intrauterine fetal death: fetal death after viability threshold and before or during delivery.
• Early neonatal death: death of a liveborn infant during day 0-6, i.e. within the first 7 completed days or 168 hours.
• Late neonatal death: death after day 7 and before 28 completed days of life.
• Neonatal death: death of a liveborn infant in the first 28 completed days of life.
• Always state the threshold used: Semmelweis/Hungarian exam notes often use GW24; international reporting may use ≥28 weeks or ≥22 weeks.

Stillbirth / Fetal Mortality Rate

• Stillbirth rate: stillbirths / total births × 1000.
• Total births: live births + stillbirths.

Early Neonatal Mortality Rate

• Early neonatal mortality rate: deaths of liveborn infants in days 0-6 / live births × 1000.

Perinatal Mortality Rate

• Perinatal mortality rate (PMR): stillbirths + early neonatal deaths / total births × 1000.
• Perinatal period: around delivery; practically late fetal period + first 7 days after birth.
• Important: PMR is not simply the arithmetic sum of fetal mortality rate and early neonatal mortality rate if denominators differ.

III. Other Useful Obstetric Indicators

Pregnancy Outcome Rates

• Abortion rate: pregnancy losses/terminations before the reporting threshold per defined denominator and period.
• Preterm birth rate: births before 37+0 weeks / total births × 100.
• Postterm birth rate: births at or after 42+0 weeks / total births × 100.
• Low birth weight rate: newborns <2500 g / live births × 100.
• Cesarean section rate: cesarean births / total births × 100.

Quality-of-Care Indicators

• Maternal: postpartum hemorrhage, severe morbidity, eclampsia, infection/sepsis, obstetric anal sphincter injury.
• Neonatal: Apgar <7 at 5 minutes, NICU admission/stay, neonatal infection, birth trauma.
• Service: antenatal-care attendance, induction rate, instrumental delivery rate, average postpartum hospitalization.
• Compare similar populations because high-risk referral centers need risk adjustment.