| Tabela VI. Spier: Revisión de la literatura de embarazos multiples. | |||
| Autor | Año | N casos | Spier |
|---|---|---|---|
| Kelly | 1991 | 40 | 16 |
| Blumenfeld | 1992 | 88 | 8 |
| Botchan | 1993 | 76 | 48 |
| Kol | 1993 | 81 | 24 |
| Lipitz | 1994 | 140 | 29 |
| Legro | 1995 | 38 | 28 |
| Manzur | 1995 | 28 | 25 |
| Total (7) | 491 | 25.4 | |
| Asch | 1997 | 82 | 28.4 |