Clinical overview
Most labour is normal, but a minority deviates — and the deviations on this objective are the ones that fill the obstetric haemorrhage, ruptured-uterus and intrapartum-asphyxia lines of the Saving Mothers and perinatal mortality reports. Complicated labour spans a spectrum: the slow-burning problem of poor progress and cephalopelvic disproportion (CPD), where the cardinal danger is obstructed labour leading to uterine rupture, fistula and sepsis; the malpresentations and malpositions that mechanically obstruct or demand a different delivery route; and the two true intrapartum emergencies on this list — shoulder dystocia and cord prolapse — where the fetus can die or be permanently injured in minutes.
For the FCOG(SA) registrar the unifying skill is recognition then decisive action. The partogram is the surveillance tool that turns a vague "slow labour" into a defined, actionable diagnosis (see Partogram use); the CTG and intermittent auscultation tell you whether the fetus is tolerating the delay (see CTG interpretation and Fetal monitoring methods). South African practice is shaped by levels of care: a woman in obstructed labour at a clinic must be recognised, stabilised and transferred, because definitive management — caesarean, instrumental delivery, theatre for the dystocia that fails — needs a doctor and an operating facility. The National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024) frames the partogram, referral lines and the obstetric emergency drills that follow.
Core knowledge
The determinants — powers, passage, passenger
Progress in labour is the product of three classically described factors. The powers are uterine contractions: adequate labour is conventionally taught as three to five contractions in ten minutes, each lasting 40–60 seconds, generating a coordinated fundal-dominant wave. The passage is the bony pelvis (gynaecoid is most favourable; android and platypelloid predispose to arrest) and the soft tissues of the cervix and perineum. The passenger is the fetus — its size, lie, presentation, position, attitude (degree of flexion) and the presence of any anomaly such as hydrocephalus. Poor progress is always a failure of one or more of these, and the diagnostic task is to decide which.
Figure J1.1 — Poor progress is a three-Ps diagnosis: augment only when contractions are inadequate and obstruction has been excluded; adequate contractions with arrest or obstruction means CPD and caesarean.
Defining poor progress
Labour is divided into the latent phase (cervix effacing and dilating to ~4–6 cm) and the active first stage. Prolonged latent phase is common, often benign, and over-diagnosing it leads to unnecessary intervention. In the active first stage, slow progress is classically defined as cervical dilatation of less than ~1 cm/hour, though contemporary guidance (the WHO Labour Care Guide, 2020 and NICE NG235 Intrapartum care, 2023) cautions against rigid linear expectations and emphasises individualised assessment with alert thresholds rather than a single universal rate (standard teaching; exact rates vary by source). The active first stage disorders are protraction (slower than expected) and arrest (no cervical change over a defined interval despite adequate contractions). The second stage is prolonged when there is no progress in descent and rotation over a defined period — broadly around two hours in a nullipara without epidural and one hour in a multipara, extended by roughly an hour with regional analgesia (standard teaching; thresholds vary by guideline and parity).
Cephalopelvic disproportion and obstructed labour
CPD means the fetal head is too large, or the maternal pelvis too small or unfavourably shaped, for safe vaginal passage. It is frequently relative — a deflexed or malpositioned head (occipitoposterior, occipitotransverse, brow) presents a larger diameter and behaves like absolute disproportion. CPD is a clinical diagnosis made in labour, not reliably predicted antenatally; clinical pelvimetry and even imaging poorly predict outcome, and a trial of labour with vigilant monitoring is the usual approach where there is no absolute contraindication.
When disproportion or malpresentation is not relieved, the result is obstructed labour — the presenting part cannot descend despite strong contractions. The classic signs are a tonically contracting, tender uterus with a palpable Bandl's ring (a pathological retraction ring rising up the abdomen), gross caput and moulding, maternal exhaustion, dehydration, oliguria and non-reassuring fetal status. Obstructed labour is the gateway to uterine rupture (see Uterine rupture), obstetric fistula (see Gynaecological fistulas), intrapartum sepsis and stillbirth, and remains a preventable cause of maternal and perinatal death in under-resourced settings. Moulding and caput are graded on the partogram precisely because their progression warns of disproportion.