The descriptive characteristics of the included studies were shown in Table
1. No randomized controlled trials were retrieved. Six cohort studies [
12‐
17] with a total of 291 participants were included in the current meta-analysis. The full text of five studies [
12‐
16] and the abstract of one study [
17] were obtained. Two studies [
12,
13] were conducted in USA, three studies [
14‐
16] were conducted in Asia (one in Thailand and two in China) and one in Italy [
17]. The participants were at least 40 years old in four studies [
14‐
17], 40 to 49 in one study [
13] and 50 or older in one study [
12]. All participants were histologically diagnosed with hydatidiform mole consisting of both partial mole and complete mole [
14,
16,
17] or only complete hydatidiform mole [
12,
13,
15]. The case group included the group of patients who received either hysterectomy [
12,
13,
16,
17] or uterine evacuation followed by hysterectomy [
14,
15]. The control group comprised patients who received only uterine evacuation. The sample size ranged from 22 to 159. The follow-up period were 3–14 years in one study [
14] and 3–12 years in another study [
15], while for the other four studies [
12,
13,
16,
17], such data were not reported. The outcome of each study was predominantly focused on the incidence of post-molar GTN. A few studies [
15,
16] additionally reported other outcomes such as median time to remission, incidence of chemotherapy resistance and time interval for diagnosing GTN. Three studies [
14‐
16] conducted comparisons of clinical characteristics between case group and control group to assess the selection bias, as a result, no selection bias were noted. However, the remaining two studies [
12,
13] did not mention such comparison.
Table 1
Description of the included studies
| China | 1978–1991 | Retrospective cohort | Age:≥40 Years | 17/13 | 3–14 | Incidence of post-molar GTN | Age, gravidity, parity |
Diagnosis: HM |
| USA | 1965–2009 | Retrospective cohort | Age:≥50 Years | 7/15 | Not reported | Incidence of post-molar GTN | Not reported |
Diagnosis: CHM |
| USA | 1965–2010 | Retrospective cohort | Age: 40–49 Years Diagnosis: CHM | 6/68 | Not reported | Incidence of post-molar GTN | Not reported |
Lertkhachonsukl 2016 [ 16] | Thailand | 2000–2015 | Retrospective cohort | Age:≥40 Years | 18/20 | Not reported | Incidence of post-molar GTN, median time to remission | Age, gestational age, initial hCG level |
Diagnosis: HM |
| Italy | 1994–2014 | Retrospective cohort | Age:≥40 Years | 12/64 | Not reported | Incidence of post-molar GTN | Not reported |
Diagnosis: HM |
| China | 2004–2013 | Retrospective cohort | Age:≥40 Years | 35/124 | 3–12 | Incidence of post-molar GTN, incidence of chemotherapy resistance, time interval for diagnosing GTN | Age, gravidity, parity, gestational age, initial hCG level, uterine enlargement, theca lutein cyst |
Diagnosis: CHM |