Pearl Index: Safety of Contraceptive Methods

Contraceptive options and their safety

The Pearl Index (PI; named after the American biologist Raymond Pearl (1879-1940)) describes the reliability of a contraceptive measure (measure of contraception) by means of the number of gravidities (pregnancies) that occurred per 1,200 cycles of use or per 100 years of use. A Pearl index of 0.1 means that one in 1,000 women using the same contraceptive (contraceptive) for one year will become pregnant.If 100 women use the same contraceptive for one year and a pregnancy occurs during this period, the Pearl index is 1. Pearl Index

Method Typical use Perfect use
No method 85 85
Female condom 10-15 2-5
Male condom 10-15 2-5
Diaphragm (mechanical contraceptive device for women) 3-16 1-6
Oral contraceptives (OCP; birth control pills) 0,5-10 0,1-0,5
IUS (intrauterine system) 0,2 0,1
Intrauterine device with copper (copper IUD). 0,2-2 0,2-2
Tubal ligation (tubal ligation; female sterilization). 0,2-3 0,2-3
Vasectomy (ligature of the vas deferens; sterilization of the male) 0,15 0,1
Coitus interruptus (interrupted sexual intercourse) 12-38 1-4
Natural family planning (NSP) (temperature method here). 6-47 3-5
Hormonal implant (hormonal implant; contraceptive sticks) 0,05-0,3 0,05
Hormone ring 0,7 0,4-0,6

In the following, reliability is given in each case as PI = x pregnancies-abbreviated as Schw. The adjusted Pearl index [correct application] is given in square brackets. Reliability level

Reliable – PI < = 0.5 Relatively reliable – PI = 2-3 Medium reliability – PI = 5-10 Unreliable – PI > 15

Contraception without the use of drugs

  • Coitus interruptus (interrupted sexual intercourse) – PI = 4-27 schw.
  • Coitus reservatus (conscious avoidance of ejaculation).
  • Periodic abstinence (Knaus-Ogino) – PI = 10-40 schw.

Contraception by intravaginal spermicidal (sperm-killing) vaginal preparations (vaginal preparations)

  • PI = approx. 29 schw.

Contraception by basal body temperature measurement

  • Exclusive intercourse “postovulationem” [after ovulation] (PI = 0.5-1 schw. ); that is, time from 2nd day after temperature rise.
  • Coitus also before ovulation (PI = about 5 gravidities); that is, at 12-month temperature measurement established earliest ovulation date (date of ovulation) – date of ovulation minus 6 days.

Contraception by mechanical means

  • Barrier methods – PI = approx. 10 schw.
  • Cervical cap (plastic or rubber cap placed over the cervix (the portio)) according to Wilde – PI = approx. 10 schw.
  • Vaginal diaphragm (vaginal pessary; flexible rubber cap) according to Mesinga – PI = approx. 10 schw.
  • Intravaginal sponge (nulliparae) – PI = about 16 schw.
  • Intravaginal sponge (Parae) – PI = approx. 32 schw.
  • Diphragma – PI = approx. 16 schw.
  • Female condom (without spermicide) – PI = approx. 21 schw.
  • Condom for the man (without spermicide) – PI = about 15 schw.
  • Intrauterine devices with copper (IUD) – PI = 0.5-1 schw. [0.6]
  • Vaginal ring – PI = approx. 8 schw. [0.3]

Caution. Intrauterine device in adolescents. Only in the case of pill intolerance or presence of contraindications. There is a risk of ascending (ascending) infection, which can lead to salpingitis (inflammation of the fallopian tubes). May be cause of extrauterine pregnancies (pregnancies outside the uterus). Therefore, adolescents should receive an intrauterine device (IUD) only in exceptional cases.

Contraception by mechanical methods containing hormones

Hormonal contraception [0.3]

  • Single-phase method – PI = 0.1 schw.
  • Three-step method – PI = 0.1 Schw.
  • Two-phase method – normophasic sequence preparations – PI = 0.1-0.2 Schw.
  • Depot progestogens – depot MPA – PI = 0.3-1 Schw. [0.3]
  • Minipill – PI = 0.8-1.5 schw. [0.3]
  • Minipill with desogestrel – PI = 0.41 schw. [0.14]
  • Progestogen-containing “pill” of the new generation – an estrogen-free pill that safely suppresses ovulation – PI = 0.14 schw. – suitable for all patients who are not allowed to take estrogens such as women over 35 years and smokers, breastfeeding, etc..
  • Contraceptive patch – PI = 8 [0.3]
  • Implant with etonogestrel (etonogestrel implant; Implanon) – PI = less than 0.1 schw [0.05].
  • Postcoital estrogen therapy – PI = 0.5 wt.

Contraception by surgical sterilization