Maternity and newborn medications

Maternity medication items are hold-and-stop skills: oxytocin off for bad tracings, Mag off when reflexes vanish, and methergine off when the blood pressure is already high.

Newborn and RhoGAM

Newborns leave the womb short on vitamin K–dependent clotting factors — limited placental transfer plus a sterile gut that has not yet made bacterial vitamin K. That gap is why IM vitamin K after birth prevents hemorrhagic disease of the newborn. Parent refusal is not a shrug: educate, document, and escalate per policy, because intracranial or GI bleed risk is the real stake. Erythromycin eye ointment blocks ophthalmia neonatorum from gonococcal or chlamydial exposure in the birth canal; timing is soon after birth per protocol, not “when the bath is done.”

• Vitamin K IM after birth — refusal raises bleed risk; document and educate.
• Erythromycin eye ointment soon after birth per protocol.
• RhoGAM prevents Rh sensitization in Rh-negative clients when indicated.

RhoGAM (Rh immune globulin) is passive anti-D antibody for an Rh-negative client who has not already formed her own anti-D. It coats fetal Rh-positive red cells that leak into maternal blood so her immune system does not learn to attack a future Rh-positive fetus. Classic windows: around 28 weeks, after sensitizing events (amniocentesis, miscarriage, trauma, abruption risk), and postpartum if the infant is Rh-positive. If the baby types Rh-negative, postpartum RhoGAM is not the usual path — there was no Rh antigen to sensitize against.

Distractor logic: skipping eye ointment “because the baby looks fine” misses occult gonococcal exposure; giving RhoGAM to an already sensitized (antibody-positive) client does not undo isoimmunization. Edge case — a sensitizing bleed at any gestational age still needs the RhoGAM conversation even if the next scheduled dose is weeks away.

Uterotonics

Oxytocin drives uterine smooth muscle. In labor that means stronger, more frequent contractions for induction or augmentation; after birth it keeps the uterus clamped down so vessels at the placental site stop bleeding. The same mechanism creates the exam trap: tachysystole (contractions stacked too tight) squeezes the placenta’s blood supply between peaks, so fetal oxygen drops and the tracing turns nonreassuring. When oxytocin is the driver of that picture, stop the infusion first — other intrauterine resuscitation steps help only after the drug fueling the problem is off. Fetal-monitor pattern detail lives in /topics/labour-and-fetal-monitoring; this chapter owns the med stop.

1. Tachysystole or nonreassuring FHR: stop oxytocin.
2. Reposition, oxygen/fluids per protocol, notify.
3. Methylergonovine: check BP — hold if hypertensive.

Methylergonovine (Methergine) is an ergot uterotonic that also vasoconstricts. That helps a boggy uterus stop bleeding, but it can spike blood pressure further in a client who is already hypertensive — so a high BP is a hold, not a “give and hope.” Classic teaching also avoids rapid IV push of methylergonovine because abrupt vascular squeeze is the risk. Postpartum hemorrhage workup and other uterotonics belong with /topics/maternity-emergencies; here the decision is whether this particular drug is safe for *this* BP.

Distractor: leaving oxytocin running while you “just reposition and call” through recurrent late decelerations — the infusion is still stacking contractions. Distractor on methergine: treating PPH with methergine at BP 170/110 because “tone is priority” — tone matters, but this drug’s vasoconstriction is the wrong tool when hypertension is already the picture. Edge case — postpartum oxytocin for tone is still a titratable infusion under protocol; tachysystole language is labor-focused, but excess dose still means notify and follow the order set rather than improvising boluses.

Tocolytics and lung maturity

Magnesium sulfate in maternity care is a high-alert infusion — used for seizure prophylaxis in preeclampsia/eclampsia pathways and in some preterm-labor protocols. At therapeutic effect it calms neuromuscular transmission; at toxic levels it flattens deep tendon reflexes, slows respirations, drops urine output, and dulls LOC. Those signs mean the drug has gone from treatment to threat: stop the infusion, support breathing, and give calcium gluconate as the ordered antidote. Electrolyte Mag toxicity rules overlap with /topics/electrolytes; obstetric items still expect you to catch absent DTRs on the drip without waiting for a lab.

Terbutaline is a beta-agonist tocolytic: it relaxes uterine muscle by stimulating beta-2 receptors, but the same class effect races the maternal heart. Marked maternal tachycardia per the parameter on the order is a hold, not a “one more dose to stop contractions.” Betamethasone (and related antenatal corticosteroids) do not stop labor — they accelerate fetal lung maturity by promoting surfactant production when preterm birth is a real risk. Timed IM doses need to be given as scheduled so the lungs get the window before delivery; delaying for convenience undercuts the point of the drug.

Distractor on Mag: charting “sedated, resting” and leaving the drip up when DTRs are gone. Distractor on terbutaline: pushing another dose into a mother already tachycardic because contractions continue. Distractor on steroids: treating betamethasone as optional comfort care instead of a timed maturity dose. Edge case — Mag toxicity assessment is scheduled (reflexes, RR, urine output, LOC); oliguria plus soft reflexes is an earlier stop cue than waiting for apnea.

Priority map