Maternal Smoking Exposure and Newborn Outcomes: Study Using Urinary Cotinine

Haseki Training and Research Hospital

Status: Not yet enrolling

Conditions: Carbon Monoxide Poisoning; Infant, Newborn; Tobacco Smoke Pollution; Maternal Exposure During Pregnancy

Study type: Observational

Funder types: Other

Identifiers

NCT07201181

141-2025

Details and patient eligibility

About

Prenatal exposure to tobacco smoke-whether from active maternal smoking or secondhand exposure-has been linked to adverse neonatal adaptation and metabolic stress. This single-center prospective observational cohort will quantify maternal smoking exposure using maternal urinary cotinine around delivery and examine its association with early neonatal physiologic and biochemical outcomes within the first 24 hours of life.

Participants will be pregnant individuals delivering at a tertiary academic hospital and their newborns. After consent, mothers will provide a urine sample for cotinine measurement. Based on pre-specified cotinine thresholds and maternal history, dyads will be classified into three exposure groups: Active smoker, Passive exposure, or No exposure. No experimental intervention is administered; all neonatal assessments are part of routine peripartum care.

Neonatal data collected (per standard practice) will include: umbilical cord blood gas parameters (pH, base excess, lactate) and fetal carboxyhemoglobin (FCOHb); birthweight; vital signs/blood pressure at ~6 hours; routine laboratory indices (e.g., hemogram, lipids such as HDL/LDL where available per unit protocol); heel-prick TSH from the standard newborn screen; and hearing screening result prior to discharge. Additional maternal and perinatal covariates (e.g., age, parity, gestational age, delivery mode, intrapartum events) will be recorded to support adjusted analyses. No extra phlebotomy beyond standard care will be performed; the study leverages existing clinical samples and measurements.

Primary objective is to determine whether higher maternal cotinine-defined exposure is associated with greater metabolic stress at birth (indexed by cord lactate and related gas parameters) and higher FCOHb. Key secondary objectives include evaluating associations with birthweight, early blood pressure, TSH, hearing screen outcomes, and routine laboratory markers. Prespecified subgroup and sensitivity analyses (e.g., by gestational age strata or delivery mode) will be conducted as feasible.

The planned sample includes approximately three cotinine-stratified cohorts recruited consecutively. Statistical analyses will follow a pre-registered plan using multivariable regression to adjust for confounders; ROC analyses may be used to explore cotinine thresholds predictive of adverse neonatal indices. Enrollment is anticipated to start October 13, 2025, with primary data collection completed within 2-3 months of recruitment initiation.

This study will provide pragmatic, prospectively collected evidence on how biochemically verified maternal tobacco exposure relates to immediate neonatal metabolic, cardiovascular, endocrine, and auditory outcomes, using measurements obtainable in routine care.

Enrollment: 126 estimated patients

Sex: All

Ages: Under 72 hours old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Liveborn neonate delivered at the study hospital, aged 0-72 hours at assessment.
• Routine umbilical cord blood gas available at birth (pH, base excess, lactate).
• Maternal urinary cotinine available around delivery (to classify exposure: active, passive, none).
• Parent/guardian provides informed consent for use of neonatal data obtained from routine care.
• Standard newborn assessments obtainable within 72 hours (e.g., birthweight, ~6-hour vitals/BP, TSH at 24-48 h, hearing screen ≤72 h per unit practice).

Exclusion criteria

• Emergent clinical scenarios where any research step could delay urgent care.
• Major congenital anomaly/condition that precludes standard assessments (e.g., cord gas not feasible) per clinician judgment.
• No maternal urine available for cotinine measurement (exposure cannot be defined).
• Prior enrollment of the same neonate (no re-enrollment).

Trial design

126 participants in 3 patient groups

Maternal Active Smoking (Cotinine-Defined)

Description:

Mother reports active cigarette smoking during pregnancy and urinary cotinine consistent with active smoking per laboratory cutoffs. Newborn outcomes (cord blood gas incl. pH/base excess/lactate, FCOHb), birthweight, 6-hour blood pressure/vitals, heel-prick TSH, hearing screen, and routine labs are recorded within 24 hours of birth. No experimental intervention is administered.

Maternal Passive Tobacco Exposure (Secondhand; Cotinine-Defined)

Description:

Mother denies active smoking but reports secondhand exposure; urinary cotinine detectable yet below active-smoker threshold per laboratory cutoffs. Same neonatal measurements and timing as other cohorts; no experimental intervention.

No Tobacco Exposure (Reference)

Description:

Mother denies smoking and secondhand exposure; urinary cotinine negative/undetectable per laboratory cutoffs. Same neonatal measurements collected within routine care; no experimental intervention.