HYPITAT: IOL vs expectant mgmt for gestational HTN after 36 weeks

Question 1

What was the aim of the HYPITAT trial?

Answer 1

To see whether IOL in women with singleton pregnancy complicated by gestational HTN or mild PET reduces severe maternal morbidity.

Question 2

Describe the HYPITAT trial study design:

Answer 2

• Study type: multicentre, open-label RCT; unable to mask allocations.
• Study population: 756

Treatment groups:

• Expectant mgmt. grp (379): maternal and fetal monitoring until spontaneous labour. IOL recommended if developed severe HTN or PET, eclampsia, HELLP, fetal distress or prolonged rupture of membranes or meconium liquor, gestation >41 week.
• IOL grp (377): induced within 24 hrs of randomisation. Usual methods of IOL.
• 397 refused randomisation but authorised use of their medical records. 82% had expectant mgmt. and 18% had IOL.

Question 3

What are the primary outcomes for the HYPITAT trial?

Answer 3

• Composite measure of poor maternal outcome:
• Maternal mortality
• Maternal morbidity: eclampsia, HELLP, pulmonary oedema, VTE, placental abruption
• Progression to severe PET
• Major PPH >1L

Question 4

What are the secondary outcomes for the HYPITAT trial?

Answer 4

• Mode of delivery
• Neonatal mortality
• Neonatal morbidity

Question 5

What were the results and conclusions from the HYPITAT trial?

Answer 5

Primary outcomes:

• More women in the expectant management grp had poor maternal outcomes (44% vs 31%) with RR 0.71.
• NNT 8
• No cases of maternal or neonatal death or eclampsia were recorded.

Secondary outcomes:

• Fewer CS needed in IOL grp.
• No fetal or neonatal deaths occurred
• No significant difference in composite neonatal morbidity.

Conclusions:
- IOL is associated with improved maternal outcome and should be advised for women with mild HTN disease beyond 37 weeks gestation.

Question 6

Why were there more Caesarean sections in the expectant mgmt grp?

Answer 6

Increased number of CS in the expectant management group likely driven by increased occurrence of severe maternal morbidity. This was proven in subgroup analyses.

Question 7

Describe the findings of the subgroup analyses for women randomised at 36-37 weeks:

Answer 7

• May benefit from expectant management.

- However small numbers of women <37 weeks so underpowered to detect difference.

Question 8

Describe the findings of the subgroup analyses for women with an unfavourable cervix:

Answer 8

• Benefit of IOL increases in women with an unfavourable cervix
• If these women are managed expectantly, time to delivery was longer compared to women with favourable cervix, therefore increasing risk of progression to severe disease and poor maternal outcomes.

Question 9

What were the two intervention groups in the HYPITAT Trial?

Answer 9

IOL

• either PG / balloon, or ARM +/- Oxytocin
• within 24h randomisation

Expectant management
- monitoring BP, proteinuria, bloods, CTG, USS
- until spontaneous deliver
- or indication for delivery
Note: of those in the expectant management group, half ended up having an IOL (72% for medical indications, the rest for maternal request)

Question 10

What were the inclusion criteria for the HYPITAT trial?

Answer 10

Singleton
36 - 41/40
Cephalic presentation

Gest HTN: DBP > 95mmHg on 2 occasions at least 6h apart
OR
Mild PET: DBP > 90mmHg on 2 occasions at least 6h apart AND proteinuria

Question 11

What the exclusion criteria of the HYPITAT trial?

Answer 11

Severe Gest HTN, SBP > 170, DBP > 110
Severe PET: proteinuria > 5g / day
Use of IV antihypertensive, HELLP, Oliguria, Pulmonary oedema or cyanosis
Pre-existing HTN treated with anti-hypertensive drugs
DM, GDM needing insulin
Renal disease, Heart disease
Suspected IUGR, abnormal CTG, fetal anomalies
Previous CS, HIV seropositivity