Indian council of medical research tubal sterilization with filshie clip

CONTRACE

INDIAN

COUNCIL

TUBAL

OF

STERILIZ

I

MEDICAL

WITH

ION

RESEARCH

F I L S H I E CLIP

A M u l t i c e n t r e Study of the ICMR Task Force on F e m a l e S t e r i l i z a t i o n D i v i s i o n of Reproductiw~ -'ology and F e r t i l i t y Control INDIAN COUNCIJ. OF MEDICAL RESEARCH A n s a r i Nagar, N e w Delhi, INDIA

IN

STI

TORS"

Raj Baweja

1

, A K •

•

Chatterjee

2

, A D

i

Engineer

3

, M P ~ogoi 4 •

o

9

y M a n u a l 5 , P. Misra 6 , U.K. Nanda 7, D .N . Pate I8 , 9 F.S. Phillips , T. Seetha I0 CO0

IN

ORS

"

I I A.D . E n g i n e e r 3 , S . Datey I , I .P . K a m b o I I , U. M a l h o t r a l , 11 11 1'1 S. M e h t a , B.N. S a x e n a , N.C. Sa na

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

M.L.N. M e d i c a l College, AI lahabad R.O.Kar dical College, C a l c u t t a K.G. M e d i c a l ColIege, L u c k n o w M e d i c a l College, Gauhati M e d i c a l College, Hadurai S.P. M e d i c a l College, Bikaner M e d i c a l College, Cuttack N.W.M. H o s p i t a l , Bombay Institute of O b s t e t r i c s & G y n a e c o l o g y , Madras vt. M a t e r n i t y Hospital, H y d e r a b a d Indian C o u n c i l of dical Research, New Delhi ABSTRACT

Female sterilization by t h e a p p l i c a t i o n of Filshe Clip Mark IV has been studied, on a p r o s p e c t i v e m u l t i c e n t r i c basis in 869 w o r n for a period of two years Sixty i n v o l u n t a r y p r e g n a n c y f o l l o w i n g ligation were reported g i v i n g a failure rate of 8.6 per 100 w ~ m e n at the end of 24 nths. M e t h o d failures were o b s e r v e d to be e v e n l y d i s t r i b u t e d t h r o u g h o u t the p e r i o d of o b s e r v a t i o n except in puerperal l i g a t i o n whom j o r i t y of the p r e g n a n c i e s a c c u s e d after six nths f o l l o w i n g ligation. Failure rate was s i g n i f i c a n t l y higher in p o s t - a b o r t a l ligations as co ared to interval ligatlons. Due to u n e x p e c t e d !v higl,or fa~|ures rate further recruit nt of study s u b j e c t s was d i s c o n t i n u e d . Info t ion on the status of the c l i p was a v a i l a b l e in o n l y 30 of the sixty failures and the clips were !~ in only 4 cases, i n d i c a t i n g improper a p p l i c a t i o n of clips. In view of hiKh failure rates a t t r i b u t a b l e to i roper clip a p p l i c a t i o n , the n~_th~d does not a p p e a r to be s u i t a b l e for p r o g r atic c o n d i t i o n s in our country. S u b m i t t e d for p u b l i c a t i o n June A c c e p t e d for p u b l i c a t i o n Septe

B E R 19

26, 1984 er 14, 1984

V O ! . 3 0 NO. 4

339

CONTRACEPTION

INTRODUCTION Female t

d of

National

sterilization

fertility control Family

which

Planning Progr

e of m a n y

le s t e r i l i z a t i o n ,

steadily

the nu

in our country,

is e x p e c t e d

1973-74

to c o n t i n u e

Considerable and

the

£

acceptors parity are

Since

accepting

v e r s a l of p r o c e d u r e

tubal o c c l u s i o n

ich

i

is the F i l s h i e

Clip and

It is

by m e a n s of a special

efficient he a i e d s tu

occluding s

1981-82

young

men w i t h demand

expands

in near

newer

techniques

mechanism.

The

future of

minimal

c h a n c e s of r e v e r s i b i l i t y . has b e e n r e p o r t e d

damage One

such

by several

(3,4).

d is bent

round

As the hinged lining to

low

for re-

issue

and yet p r o d u c e

its a p p l i c a t i o n

applicator.

tile trends

family p l a n n i n g

the p o t e n t i a l

to e v a l u a t e

long

increased

and the rise

r e c e n t l y on

age and p a r i t y of

effective

India.

is rising

having

Clip is made of t i t a n i u m w i t h

12.7

the rubber

including

of

also.

as an i m p o r t a n t

tube~ its soft r u b b e r

occurs

during

prevalent

onent

in p a r t i c u l a r ,

re r e l a t i v e l y

to be a safe t e c h n i q u e

lining.

countries

focused

sterilization,

are safe,

IV F i l s h i e

the f a l l o p i a n

and

s desirable

The M a r k

necrosis

has b e e n

thereby offering better

estigators,

rubber

ar future

w o u l d emerge

it beco

to the tubes,

re

tubal

In v i e w of this

agent

in the

lications of the d e c l i n i n g (1,2).

co

er of such o p e r a t i o n s

to 2 78 m i l l i o n s

attention

and w i d e l y

forms a s i g n i f i c a n t

The acc~.p~ab ~[i~-y of fe

f r o m 0.54 m i l l i o n

340

is a h i g h l y e f f e c t i v e

i c h o c c a s io na I I y s e p a r a t e.

metal

silicon

fa!lopian

clip

is c o m p r e s s e d .

ep the

tube e

the

inner

is locked on

When

lumen b l o c k e d

ntually divides,

tube

tubal

- a very leaving t

T h e c 1 i p u s u a I Iy re m a in s

OC

BER 19

VOL. 3 0 N O . 4

CONTRACE

attached

a thin d

to the

layer

of p e r i t o n e u m .

age in co

close to t

re c

host tissue within

The clip

is c o n s i d e r e d

arison to the standard P o ~ r o y ' s utsrus

to

produce

technique

less

and is applied

a I i s at i o n .

with Filshie C l i p s -

located

Hospitals

and efficacy o f

dical

method of Filshie

country,

rotomy

the

tube.

D

culdoto

at

I0 Teaching Hospitals

from Nov

le

bet 1980 to No nstrated

were

centres,

consisted

the

study

re

De

graphic

characteristics,

othe~ise

of re

scheduled

ination

of

I00 women

at

BER 19

d up a t

1,3,6,12,

er

in

1983.

The

and practised by the

be a p p l i e d

one,

whe

n reques=ing

in

at

mini lapa-

clip

appliaauion

obstetric

of

t

uni

18 a n d 24

VOL. 3 0 NO. 4

for

profile,

nths

profo

n enrolled

a period

~nstrual

at ion

related

and complications

precoded

uld be

Clips.

intervals

d info clip

sterilization.

om tubal occlusion

scheduled

findings,

application corded

to

cept

achieved by the application of Hark IV Filshie

follo

situated

.

s to enrol

ex

~he safety

evaluate

S

The c l i p s

participating

The study sa

d pelvic

) in I0 Teaching

country t o

Clip application was de

on a model

at

S

ert~en

invest.igators

Each centre

study

this p r o c e d u r e .

different par~s of C

be done

a collaborative

n Trust,

in different parts of t

e study was u

by all

search undertook

Mark IV (Gift of Si

RI

st

s covered wich

(2 cm) thereby offering higher chances of successful

Indian Council o£

~uld

it and always beco

ION

e.

following

The the

of

2 years.

history, to

the

during

physical ease

or

hospital

follow-up operation

for

was and

34?,

C"O N T R A C E

IO N

~formation co

rega

1 ic at £o ns etings

held

of

and

nstruation,

f a i lu re s

the m e d i c a l

to e n s u r e

One of

ing

due

uniform

to

local

centres

centre

te

s e que I ae o f I ig at io n.

table

t

d

d test

could

of si

sequelae

or

sponsible

rk

for d a y - c o - d a y

in d a t a c o l l e c t i o n

could

not be Me t hod

other

Per i o d i c a I

inistrative

that

pattern,

o r de d o n f o I low-u p f o rms.

thodology

a

(73 cases)

re r

officers

the p a r t i c i p d t i n g

schedule

menstrual

not

adhere

problems included

to the

and

nclature.

follow-up

therefore

data

for the a n a l y s i s

f a i Iu re r a t e s

ificance

and no

s based

re

from

of

long-

r e c omp u t e d u s i n g I i fe on C h i - s q u a r e

(5,6).

SULTS A focal were

enrolled

was closed

for

3 per

cipating

centres

sequelae

of

G

E

the

three capita

all

s

because ~r

re o c c l u d e d

r regis=ration rate

As ~ n t i o n e d

(73 c a s e s ) w a s

included

tu

Furt

failure

as t

95%

f r o m the

of non-availability the a n a l y s i s

of

i

with

of w o m e n Io

earlier, d a t a

excluded

the p a r t i c i p a t i n g

(76.6%)enrolled s t

per cent into

om

r

to the

limit

from one

analysis of

Filshie

of

study failures

of the part i-

of l o n g - r e

follow-up.

ediate

Clips

However,

sequelae

of

l igation.

FILE

men

also e x p l a

of h i g h

liganion

Since of

study.

I00 users.

cases were P

n in

the

cause

exceeded

these

342

of 869

high of

was

n

for t

literacy n

cen=res

rate

re u r b a n

study

re f r o m u r b a n

(66.3Z)

re h o u s e w i v e s

less than Rs. 100 p e r

based,

obser and

d

the m a j o r i t y areas.

in the

in 59.4Z,

the

study. family

This Ninetyper

nth.

BE R 1~9

V O L . 3 0 NO. 4

CONTRACE

Average

age of w o m e n

years s respectively.

and

~¢erage

their husbands

number

of p r e g n a n c i e s

3.8 and 3.53 respcctively~ w i t h an average s t e r l L i z a t l o n (Table of w o m e n without

I). ~n

interesting

any d a u g h t e r s

were

accepted

of 3.4

28.4 and

living

fact was

years

and

34.8

live b i r t h s

were

children

that w h i l e

sterilization,

ION

at the ~ime of

12.3 per cent

tl,is number was

only 3.2 per cent w h e n they had no ~ n s . TABLE

I:

OBSTETRIC

P

FILE

rage N o . +

S.D.

m

Age of wo

n

28.4

Age of husband

+ 4.6

34.8

+ 5 6 m

Pregna_~ncies

3.8

+

I. 3

Live births

3.5

+

I.I

Abort ions (Spont. +Induc.)

0.3

+ 0.3

Living

3.4

+

No.

FACTORS

~

_

GNOS!S

of S t e r i l i z a t i o n -

-

............

Filshie after c u l d o t o m y different

P

I .0

869

of w o r n

INFLUENCING

ute and Ti ,

Children

ti~

.__

.....

~ : - - -

clips were in 65

applied

(7.5Z)

intervals

_

at

~~n.

in r e l a t i o n

BER 1 9 8 4 VOL. 3 0 NO. 4

laparo=omy

in 804

The procedure =o p r e g n a n c y

(92.5%)

~~n

was u n d e r t a k e n (Table

and aC

II).

343

CONTRACE

I LE II"

UTE

D TIME OF STERILIZATION

Mini ....N O ;

s t-par=urn

to to . . . . . . . . . . . . . . . . . . . . . . . . . . . .

369

st-abortal

cu lao t

% ......................

No.

g

45.9

37

4.7

I

I .5

Co n c u r r e n t

C. S.

12

1.4

Concurrent

~steroto

42

5.2

166

20.7

43

66.2

Interval

178

22. I

2!

32.3

Total

804

ncurrent

MTP

100.0

65

100.0

ae s t he s ia

......................................................... : : . : , , : ~ : = ~

~

The choice of anaesthetic operator.

general re

Spinal

anaesthesia

was

was

employed

a n a e s t h e s i a with or without

ining

28.3%

were

single case where acupuncture

do

under

sterilization

left to the discretion

local

is

34.3Z

intubation

the

cases,

in 37.3% and the

anaesthesia.

(Minilap)

of

of the

There

was perfor

was

a

d under

sthesia.

t i b io t i c s

ophylaccic

antibiotics

were given to

(95. I%) as per the usual practice

344

jority of subjects

of the hospital.

R 19

VOL. 3 0 N O . 4

CONTRACEPTION

CO

LICATIONS

O p e r a t i v e Difficu fries

Operative difficulty

d i f f i c u l t i e s were e x p e r i e n c e d

in o p e n i n g

and a p p l i c a t i o n

t

peritoneum,

approaching

of the clips at the proper site

it was difficult

to open

10 cases.

This

o u l l a r y end because of

site.

(Table

llI).

In tw~ w o r n In 4 women

fn two it was a p p l i e d

large vessels

included

and e x p o s i n g the tubes,

the p e r i t o n e u m because of obesity.

clips could not be a p p l i e d at correct near the

in

laterally

in the m e s o s a l p i n x

one case

it was applied at th.- fimbrial end as there was difficulty

ing d o ~

left tube since the o p e r a t i o n was being p e r f o r ~ d

In one w o m a n a catgut

stitch was applied

lateral

that the clip had not been properly applied.

and in in bring-

through culdotomy.

to the clip as it was

In one ocher

subject

also clip

a p p l i c a t i o n was not u n s a t i s f a c t o r y

as the angle of the clip remained

above t h e m e s o s a l p i n g e a l

the

border

of

felt

2

tube.

In one w o m a n fimbrial end of tube was torn and had to he stitched and

in another case one tube

t t r a n s e c t e d d u r i n g operation.

in this case was c a r r i e d out by Pomeroy's

The

ligation

technique.

Infections -._~_

................ -

_

One w o m a n d e v e l o ~ d

pelvic

infection, and urinary

in 2 o t h e r cases d u r i n g their h o s p i t a l

B E R 19

VOL. 30 NO. 4

stay.

All

infection was seen

3 responded

to treatment.

345

CONTRACE

ION

BLE llI:

Difficulty

No.

Difficulty peritoneum

in o p e n l n g

2

IES

DURING

OPER

ION

Ti of S t e r i l La t io n / P r o c e d u r e

Remarks

Both wo n we re o b e s e , one of t h e m had p r e v i ous LSCS Scar

Postpartum/ Minilap.

Clips c o u l d not be plied at correct site

3

Clips c o u l d not be a p p l i e d at c o r r e c t S ire

I

ncurrent Culdoto

Injury

to tube

!

-d 0,-

Injury

to

1

Postaborta!/ Minilaparotomy

One tube got trallsectcd d u r i n g operat ion a n d was l i g a t e d by P o m e r o y ' s technique.

2

Postpartum/ Minilaparotomy

In one case angle of the c l i p r e m a i n e d at 2 n ~ above the sosalpinx b o r d e r of t tube and in a n o t h e r m a n cat gut st itch s applied with clip ~ sit .

tube

Unsat is fac t ory

applicat

6

DIFFICU

ion

-do.-

In all three cases tubes had large vessels; in t clips were a p p l i e d l a t e r a l l y t and in one, o n an a m p o u l l a r y port ion of the tube in a n a v a s c u lar area. P/

It was d i f f i c u l t to b r i n g do the tube v a g i n a l ly so c l i p was a p p l i e d n e a r the fimbrial end of the t u be T h e r e was slight tear n e a r the fimbrial end w h i c h was st itched.

R 19

V

3 0 NO. 4

CONTRACE

Wound

Healing_ per

the usual

day of s t e r i l i z a t i o n tim.

It was o f the

6 wo

and p a r t i a l

n

en applied

practice

the

and the w o u n d

satisfactorily

peccive

n are d i s c h a r ~ d

was

healed

ex

in

dehiscence

was

at m l n i l a p a r o t o

ined re

route of s t e r i l i z a t i o n .

IV:

on 6 c h l 7 t h

in all c a s e s

than 86% of wo

Stitch

found

(Table BLE

abscess

in one where

at n

this

irres-

occurred

in

the c l i p s

had

IV). WOUND HEALING

................................ ~ , ~ , ~ ~ H : ~ . , ~ , ~ , , ~ , . : ~ _ _ ~ . ~

~

~

~ : ~ . ~ w

.

Hinilaparoto :~: ~

-

No.

u

~

~

...........~.

_

~

~ _ , L ,

........................

z

NO~ .............................X

69 4

86 4

56

86.2

Induration

103

!2.8

9

13.8

6

0.7

1

0.1

65

100 .0

abscess

P a r e ial d e h i s c e n c e

tal

Ste ril izaC ion After 796 s u b j e c = s

at

R

19

100.0

i lure s excluding

the

data

from 9 centres

flow up races cent

804

¸¸-~

Cu Idoto

~

Healed

Stitch

per

ION

dropped

re

steadily

I y e a r and furt

VOL. 30 NO. 4

from o

centre

considered fr

98.1

(73 cases), =he

for a n a l y s i s

in this s e c t i o n .

p e r cent at o n e

r to 76.4 p e r cent

ac t

remaining

years

nth to 88.6 (Table

V).

347

CONTRACE

ION

TAB

V:

LLOW-UP PER CENT

e=nth

0

Three

98. I

nths

95.4

Six m~nths lye

92.3

months

88.6

Eighteen ~ n t h s

8 3.4

nty-four ~ n t h s

A total of 60 involuntary inception of the study, 100 w o r n

76.4

pregnancies

giving a gross cumulative

at the end of 24 months.

w i t h i n one year of sterilization group,

comparatively

~nths

of ligation

have been reported

Forty-two of these

(5.8 ~ r

fewer pregnancies

100 wo

infertility or

failure rate was significantly n) as co

the end of t ~ n t y - f o u r

8

failures occurred In the post-partum

than during later period of observations

tion due to p o s t - p a r t u m

100

n).

rate of 8.6 per

were reported during

This could probably be due to possible protection

per

failure

ligations

of o b s e r v a t i o n

first six (Table Vl).

from the risk of concepIt is not clear why the

higher in post-abortal

ared to interval ~nths

lactation.

since the

ligation

(5.9 per

group

100 w o r n )

(11.9 at

(Table VI).

R 19

VOL. 3 0 NO. 4

CONTRACE

BLE VI: .

.

.

.

.

.

.

.

Groups

.

.

.

G :::

SS C

= = ~

L

IVE FAILU

E

..........................................................................................................

~.

Cu lative failure rate/t00 w o m e n nths 12 months 18 months 24

6

ION

nths

Pos t - p a r t u m (356)

0.9

4.2

6.5

8.5

Post-abortal

4.9

9.6

I !. 3

11.9

Interval (192)

2.8

4.6

5.9

5.9

All G r o u p s *

2.7

5.8

7.5

8.6

(2 2 ~ )

(769)

Figures

in p a r a n t h e s i s

*Excludes

T

and o

nths of s t e r i l i z a t i o n the operation.

e r of subjects

12 c a e s a r i a n

nths after

of these

by culdotomy)

n were

ligation to

lost to loll

All these

by t h e be

two

period ~ f t e r

failures have been reported as late

in 65

-up after sterilization.

r e m a i n i n g 63 wo

n

n.

roy*s

roperly

VOL. 3 0 NO. 4

technique

applied

in

all

four u

P, and t

after 5 wo

Two

Five failures

o were available

n were resterilized;

roscopic s t e r i l i z a t i o n c o n c u r r e n t l y w i t h

BER 19

nstrual

ur of these pregnancies had o c c u r r e d w i t h i n six

sterilization.

£ou

period

c o n c e i v e d wi=hin

a p p r o a c h was used at only one centre

follow-up,

re

interval

sterilization.

been reported out of t

peral

cases.

after having only one

On the other hand,

Culdot

ha

and

m e n in w h o m clips were applied during

(one by mini l aparo to

as 22

indicates nu

15 ~ s t e r o t o m i e s

a nor

er

for

nths of nt

lapa-

fifth had a puer-

I delivery.

Clips

n.

349

C O N"I ...... ='R ACE

Manage

ION

nt of

ilure s

dical

te

ination of p r e g n a n c y

failure cases.

Forty-three

t

Se

procedure.

pr No

ature) while further

60

n

the outco

i n f o r m a t i o n is

fai I u r e

contraception.

nted

to

is awaited

P, ~ut only 39 underwent

continue

with

the

3 had

I

in the r e m a i n i n g

i n s e r ted

ligations,

pregnancy

(six full term and one 10 subjects.

men who opted

s te r £ I izat ion oper at ions ha

Of the thirty-t

by m i n i l a p a r o t o

for

ilable about the 4

.

cases;

included 4 p u e r p e r a l

P) was advised to all the 60

had normal d e l i v e r i e s

but did not ge t it do o f the

n opted

nteen

d seven of these h

(

for MTP

bee n do ne - 32

and o

op te d fo r o r a I

resterilization

o p e r a t i o n s which

five were p e r f o r m e d by l aparoscopy,

and in one case,

the husband

opted for vasecto

26

.

DISCUSSION

Since s t e r i l i z a t i o n regulation,

it s

1ere, and =he

those

ich c

ine

failure

rate.

st a c c e p t x T

um sa

erstreet

of all o t h e r

350

in 1970 (7) a thods are

!e

method of fertility fami]ies

thods of s t e r i l i z a t i o n will be

ty w i t h maxi

usual y a r d s t i c k

is that of the s t a n d a r d by

a permanent

uld ideally be a d v o c a t e d o n l y for those whose

are co

a 1

is e s s e n t i a l l y

r

m effective

ss, i.e. w i t h

asuring the failure rate

roy t e c h n i q u e w h i c h was reported as 3.3/I000 it is against

this that the e f f e c t i v e n e s s

asured.

B E R 19

V O L . 3 0 NO. 4

CONTRACE

In recent

years,

however,

as already pointed out earlier,

women with less than 3 living children are opting hence a new di that beco led to the

introduction

and plastic nts,

than

bands

of new

it is clai thods

the Fi!shie

the Filshie clip that the

o

at

Iborne

that for the widely search decided

Since

These

it was clai

unt of tissue destruction was rings,

d for

less than even

and as the failure rate reported

in 1981 on the basis of worldwide

in o

perfor

d Po

ning Progr

roy

thod,

Iticentric

t

and

trials involving

r 32 centres, was only 3/I000,~.e.

no higher than

Indian Council of

dica[

trial to see how the method

ds of recently qualified

be the case if the m e t h o d were

to be included

junior operators in t

National

as Family

uld Plan-

of the country. failure

n foil

is one prototype.

byelectrocautery-

to launch this

u!d fare in the h

tably high,

clip

ring or metal

and Casey at the Vllth Asian Oceanic Congress of Obstetrics

r 4000 patients

T

has

ch less damage to the fallopian tube

that caused by the widely used Fallo

Gynaecology

should

surgical e x c i s i o n of a portion of the tube,-or

d e s t r u c t i o n of its continuity

by Filshie

This

and

thods of tubal o c c l u s i o n by the appli-

d, p r o d u c e

involving

thod,

the field.

such as the Yoon band or Fallope

clips of which

young

of increased chances of reversibility,

n e c e s s a r y at a later date has entered

cation of p l a s t i c

a

that

nsion,

for this

ION

rate in this p r o s p e c t i v e

sixty failures d out of 869

R 19

trial was u n f o r t u n a t e l y

being recorded at the end of one year n e n r o l l e d for t

3 0 NO. 4

unaccep-

in 676

study.

351

CONTRACE

Infor

tion on the status of the clips was available

o£ the

60 f a i l u r e s

failure

(impro

~sponsible that prior

all

ION

and

clips

pplication

were ~

in only

clips)

was t h e r e f o r e

of

for the high rate of failure and this

operators

Co

the

c

t

~re ence

From the e

sho nt

of

t the

correct

erience of t

suit

(1,8).

le for the progra

the major

factor

in spite of the fact o f clip application

specialized skill for reducing operator's

higher than that of standard Po

ring application

Operator

present study one may conclude that

The failure rate (use-effectiveness)

significantly

4 cases.

study.

Filshie Clip application requires failures.

thod

in only 30

Therefore, atic co

the

of 8.6 per I00 women is roy technique

and Falope

thod does not appear to be

itions prevailing in developing countries,

except in the hands of experienced operator. reversals

have been atte

ted in any of the subjects

in the

study so far and no ectopic pregnancies have been reported.

352

1 9 8 4 VOL. 3 0 NO. 4

CONTRACE

ION

FERENCES

I.

Sequelae of Tubal Sterilization, New Delh£, 1982.

2.

Ross J.A. : acceptors.

3.

VIIth Asian and Oceanic Congress of Obstetrics and Gynecology Iborne 1981. E d . W i l l l a m A.W. Wa l i a r s and Carlwood.

0

Collaborative

Study of ICMR,

Declines in age and family size of family plannlng Studies i n Family Planning, No. I0, 290, 1979.

Paterson Peter: Laparoscopic sterilization with Filshle cllp under local anesthesia. Med. J. Aust. 2:476-477, 1982.

5.

Tietz C., Reco ended procedures for of tntrauteirne contraception. Stud.

6.

Azen S.P., S. y, G. Pike end 3. Casagrande. Some susgested improve nto to current statlstical methods of analysing contraceptive efficacy. J. Chron. Dis. 29:649-666, 1976.

7.

Overstreet F.W.: Female sterilization, Planning and Contraceptive t 2nd E d i t i o n Williams, Baltimore, pp. 414, 1970.

8.

Yoon I.B. and Po!iakoft, S.R.: Laparscoplc A follow-up report on the Yoon Falope Ring p. d. 23:76-80, 1979.

R 19

VOL. 3 0 NO. 4

the statistical Plann. 4: 35-42,

evaluation 1973.

nual of Family (edited by H.S. Caddarone). tubal ligation: thodology. J.

353