Version 3.3.0

Version 3.3.0 (2026-03-27)

• Made scalar time parameters behave more consistently by removing the ability to index them if they are scalars, and also having np.iterable() return False for such parameters
• Backwards-compatibility notes: This change may cause simulation results to be numerically different, as it will cause distributions to use a more efficient sampling method for affected scalar parameters (in such cases, there is likely to be a performance increase)

Pregnancy loss and neonatal death classification

• Added background pregnancy loss via p_loss parameter in Pregnancy. Per-timestep hazard means early losses are naturally more common.
• Prenatal deaths are now classified by gestational age: miscarriage (<20w) vs stillbirth (>=20w), controlled by loss_threshold parameter.
• Preterm (<37w) and very preterm (<32w) births are now classified and tracked, with configurable thresholds via preterm_threshold and very_preterm_threshold.
• Added passive neonatal death detection: deaths of agents aged 0-28 days are classified as neonatal deaths.
• New results: miscarriages, stillbirths, nnds, n_preterm, n_very_preterm, preterm_rate.
• New states on newborns: preterm, very_preterm, neonatal_death.
• Removed unused _p_miscarriage and _p_stillbirth placeholder distributions.
• Migration: n_pregnancies_this_step and n_births_this_step counters removed; use results directly.

Generic congenital outcome framework

• Added set_congenital() to the base Infection class. Diseases opt in by defining birth_outcome_keys and birth_outcomes in pars.
• Added step_congenital() helper to process scheduled congenital events at delivery time.
• Added _assign_congenital_outcomes() override point for state- or GA-dependent outcome probabilities.
• Death outcomes (miscarriage, nnd, stillborn) trigger request_death; non-lethal outcomes set a bool state.

FetalHealth improvements

• Simplified apply_timing_shift, apply_growth_restriction, reverse_timing_shift, reverse_growth_restriction — removed redundant pregnancy filtering and type coercions.
• n_exposures state tracks disease exposures during pregnancy (connectors increment directly via fh.n_exposures[uids] += 1).
• Added interp_fn parameter for customizing birth weight interpolation.
• Negative growth penalties (growth boost, e.g. GDM macrosomia) are now additive rather than using diminishing returns.

MNCH examples

• Added starsim_examples/mnch/ with reusable maternal/newborn/child health examples:

  • CongenitalDisease: simple SIR with congenital outcomes via the generic framework.
  • NeonatalSepsis: SIR that infects/kills newborns, useful for testing NND detection.
  • fetal_infection: connector that damages fetal health when mothers are infected.
  • treat_pregnant: intervention that treats infected pregnant women.

• GitHub info: PR 1269