It is not permissible for one of the spouses to prevent pregnancy without the consent of the other
It is haram for her to use contraceptives without her husband’s consent, because it is the right of both husband and wife to have children. Hence the scholars said that it is haram for the husband to withdraw from his wife without his wife’s consent.
“Withdraw” here refers to ejaculating outside the vagina (‘azl) lest the woman become pregnant. But if both spouses agree to taking these pills, it is permissible, because that is akin to ‘azl, which was practised by the Sahabah, as Jabir (may Allaah be pleased with him) said: We used to practise ‘azl at the time when the Quran was being revealed.
In other words, if it had been forbidden the Quran would have forbidden it. However, it is better not to take these pills because that goes against the wishes of the Prophet (peace and blessings of Allah be upon him) for this ummah, that they should have many children.
I tell you that the ones who first invented these pills were the Jews and other enemies of the Muslims, who want to eradicate this ummah and reduce its numbers, and leave it dependent upon others, because the smaller their numbers the smaller their productivity, and the greater their numbers the greater their productivity – in agriculture, industry, commerce and in every field. Nations are feared more than others if they are greater in number, even if they are not advanced in industry, because large numbers alarm the enemy.
So we call upon the Muslims to have many children, so long as there are no circumstances such as sickness or poor health on the woman’s part or she cannot give birth without surgical intervention, because these are cases of necessity and cases of necessity are subject to different rulings.
Ash-Shaykh Ibn ‘Uthaymeen, Fatawa al-Mar’ah al-Muslimah, 2/556
Please see also question no. 21169.
If taking these pills is haram, then it is haram to help her to obtain them, because Allah says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression”