Weitz 2013.
| Methods | Cohort study carried out over 4 years in California, USA | |
| Participants | 11,487 women completed the study. The study was carried out in a private facility hospital and private clinic in California, USA between August 2007 and August 2011 Eligibility: Aged 16 years or older (18 years at Planned Parenthood affiliates), seeking a first trimester aspiration abortion (facilities self defined this as < 12 or < 14 weeks gestation by ultrasound), could speak English or Spanish Patients were excluded if they requested general anaesthesia or did not meet the health‐related criteria (unexplained historical, physical or laboratory findings or known or suspected cervical or uterine abnormalities) |
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| Interventions | In this prospective, observational cohort study, NPs, CNMs and PAs from 5 partner organisations (4 Planned Parenthood affiliates and KPNC) The study compared complication rates within 4 weeks of aspiration abortion for nurse practitioners, certified nurse midwives and physician assistants to those of physicians. Providers were trained to competency in the provision of aspiration abortion (a minimum of 40 procedures over 6 clinical days, with competence assessed by an authorised physician trainer) and had a California professional licence and basic life support. Providers performed aspiration abortion on participants with < 14 weeks gestation. Follow‐up was within 4 weeks of procedure MLPs and doctors worked from the same site |
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| Outcomes | The primary outcome was the difference in the incidence of complications within 4 weeks of the aspiration abortion between NPs, CNMs and PAs and physicians Complications were categorised as immediate (occurring before leaving the facility) and delayed (occurring < 4 weeks after the procedure) Complications were classified as major if the patient required hospital admission, surgery or a blood transfusion and minor if they were treated at home or in an outpatient setting |
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| Notes | — | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | No random sequence generation, however a lack of randomisation was adjusted for in analysis using propensity score matching |
| Allocation concealment (selection bias) | High risk | None |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | The participant was aware of the provider type. We do not consider this to be a bias because this is part of the intervention. If MLPs are to perform abortion procedures outside of study conditions, we would expect patients to be aware of the provider type. We therefore do not consider the lack of blinding to provider type to bias the results of the study |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | A further limitation of the study is that the health care provider who initially identified a complication was not blinded to the type of provider who performed the abortion |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 30% loss to follow‐up Complications between groups compared "Although postprocedure complications may have been missed among patients for whom we did not have follow‐up data, given the nondifferential follow‐up rates between provider groups, we would expect unidentified complications to be equally distributed between groups, leaving the risk difference unaffected." |
| Selective reporting (reporting bias) | Low risk | Protocol published |
| Other bias | Low risk | The study appears to be free of other sources of bias |
CNM: certified nurse midwife hCG: human chorionic gonadotropin KPNC: Kaiser Permanente of Northern California MLP: mid‐level provider MSI: Marie Stopes International MVA: manual vacuum aspiration NGO: non‐governmental organisation NP: nurse practitioner PA: physician assistant POC: products of conception WHO: World Health Organization