Under Lenin, divorce was made much easier. Abortion was also legalised. This is because of a Marxist belief that marriage was a bourgeois institution, and that women were to be "freed from the bondage of children and family". This didn't last too long however, and the party (even under Lenin) soon came to question it's previous decisions. By the late 1930s, divorce rates in the Soviet Union were the highest in Europe at one divorce for every two marriages.
This led Stalin to embark on the "Great Retreat" whereby Stalin came to stress that the family was a stabilizing influence on society. Stalin reasoned that in order to be a good communist, one had to be a good citizen, and in order to become a good citizen, one had to be a good husband/father/wife/mother.
Industrialisation and collectivisation had caused large social unrest, and Stalin stressed good ol' family values as a remedy to this, attaching traditional values to women, such as their roles as home-makers and child-raisers. He also noticed that there were a great number of orphaned children living on the streets, formed into gangs. This further caused Stalin to recreate the importance of the family in the Soviet Union.
In June 1936, he reversed much of the social policy regarding women which had been written under Lenin, importantly:
Marriages now had to be registered to be recognised.
Divorce was once again made difficult
Abortion rights were restricted
The family was declared the "basis of Soviet society"
Homosexuality was made illegal
This put an end most of the progressiveness Soviet social policy may have once had.
Also, as birthrates were falling and many men were dying in the Second World War, in July 1944, the USSR introduced measures to re-affirm the values of the family, as well as to incentivise women to have more children. In actual fact, these measures restricted women's rights even further. As of July 1944:
Divorce was made even harder
Abortion was made totally illegal
Mothers with more than two children were declared "heroines of the revolution"
Parents with fewer than two children face heavier taxes
The right to inherit family property (restricted under Lenin) was re-established.
Though Soviet propaganda talked a lot about gender equality, in actual fact there was very little. In 1936, Stalin created a "Housewives' Movement" which was charged with "civilising the tastes" and improving the working conditions of women, but in actual fact the USSR was so rapt on it's war economy that the group received little attention or funding, a long with almost all women's organisations.
Some women gained income and status under Stalin, but these were rare cases, and almost always unmarried and childless women.
Women did become better represented in the workforce, largely due to a lack of men because of the war. in 1936, there were 9 million women in the industrial workforce of the USSR. By 1945, there were 15 million. In fact, by 1945, half of all Soviet Workers were female. In the Soviet armed forces themselves, over half a million women fought.
Despite women's massive contributions to the USSR and the Soviet war effort, equality was not really achieved. In real terms, women's pay fell between 1930 and 1945.